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M Jalkanen

Publications and source records attributed to M Jalkanen.

At least 73 records · Page 4Linked to original sources
PubMed1992

Transient expression of syndecan in mesenchymal cell aggregates of the embryonic kidney.

Induction of the embryonic kidney mesenchyme is followed by formation of cell aggregates which subsequently transform into epithelial tubules. Syndecan, which binds various matrix components and growth factors, is a candidate molecule to be involved in this process. We have analyzed the changes in the expression of syndecan during tubule morphogenesis by using in situ hybridization and slot-blot analysis. The expression pattern of syndecan was compared with the distribution of cell proliferation analyzed by immunohistochemistry. Furthermore, the expression of syndecan during formation of the pretubular aggregates was studied in hanging-drop cultures of experimentally induced mesenchymal cells. Syndecan mRNA was expressed in the metanephric mesenchyme prior to induction, was intensely present during formation of the pretubular cell aggregates, but was lost during maturation of the nephron. Slot-blot analyses of the kidney mesenchymes (11-day kidney) cultured in a transfilter situation with a heterotypic inductor tissue that triggers a complete tubulogenic program in the nephric mesenchyme during the first 24 hr suggested the presence of syndecan mRNA in the uninduced mesenchymes with no change during induction. Expression of mRNA was stimulated later (13-day kidney) followed by subsequent decrease. Immunoisolation of sulfate-labeled syndecan, however, revealed a marked stimulation in the induced kidney mesenchyme during the first 24-hr inductive period when the DNA level still remained constant. In hanging-drop cultures where either induced or uninduced mesenchymal cells were dissociated and reaggregated, syndecan was detected only in the induced and aggregating mesenchymal cells. Double-immunostaining demonstrated a close correlation between syndecan expression and cell proliferation analyzed by bromodeoxyuridine incorporation. Thus, it appears that syndecan expression in the mesenchyme is initially induced post-transcriptionally and later during differentiation at the mRNA level. Syndecan may have a dual function during early kidney morphogenesis; it may be involved in cell aggregation through its adhesive properties, and it may contribute to proliferation of the induced mesenchymal cells by binding growth factors.

Animals↗
PubMed1992

Neurite growth-promoting protein (amphoterin, p30) binds syndecan.

A new ligand for syndecan (a cell surface heparan sulfate-rich proteoglycan) has been discovered. In the solid-phase binding assay utilizing small nitrocellulose discs to immobilize matrix molecules, binding of syndecan to neurite growth-promoting protein, p30/amphoterin, was observed. This binding was strongly dependent on the concentration of amphoterin used to coat the discs, but was saturable with an excess amount of syndecan. The interaction was inhibitable with heparan sulfate and heparin but less effectively with chondroitin sulfate, indicating that heparan sulfate chains of syndecan were involved in the binding. Anti-amphoterin antibodies inhibited the binding partially. Mouse mammary epithelial cells were shown to bind amphoterin directly but not after trypsin treatment or in the presence of heparin and to produce amphoterin in the extracellular space. Both syndecan and amphoterin were found to localize on lateral surfaces of newly adhered mammary epithelial cells. Toward confluency amphoterin amounts decreased. Because amphoterin can be localized to the same sites with syndecan and because of their interaction, amphoterin is a new putative pericellular ligand for syndecan. These interactions may be involved in the regulation of cell behavior.

Animals↗
PubMed1992

Lymphocyte CD44 binds the COOH-terminal heparin-binding domain of fibronectin.

The lymphocyte-high endothelial venule (HEV) cell interaction is an essential element of the immune system, as it controls lymphocyte recirculation between blood and lymphoid organs in the body. This interaction involves an 85-95-kD class of lymphocyte surface glycoprotein(s), CD44. A subset of lymphocyte CD44 molecules is modified by covalent linkage to chondroitin sulfate (Jalkanen, S., M. Jalkanen, R. Bargatze, M. Tammi, and E. C. Butcher. 1988. J. Immunol. 141:1615-1623). In this work, we show that removal of chondroitin sulfate by chondroitinase treatment of lymphocytes or incubation of HEV with chondroitin sulfate does not significantly inhibit lymphocyte binding to HEV, suggesting that chondroitin sulfate is not involved in endothelial cell recognition of lymphocytes. Affinity-purified CD44 antigen was, on the other hand, observed to bind native Type I collagen fibrils, laminin, and fibronectin, but not gelatin. Binding to fibronectin was studied more closely, and it was found to be mediated through the chondroitin sulfate-containing form of the molecule. The binding site on fibronectin was the COOH-terminal heparin binding domain, because (a) the COOH-terminal heparin-binding fragment of fibronectin-bound isolated CD44 antigen; (b) chondroitin sulfate inhibited this binding; and (c) finally, the ectodomain of another cell surface proteoglycan, syndecan, which is known to bind the COOH-terminal heparin binding domain of fibronectin (Saunders, S., and M. Bernfield. 1988. J. Cell Biol. 106: 423-430), inhibited binding of CD44 both to intact fibronectin and to its heparin binding domain. Moreover, inhibition studies showed that binding of a lymphoblastoid cell line, KCA, to heparin binding peptides from COOH-terminal heparin binding fragment of fibronectin was mediated via CD44. These findings suggest that recirculating lymphocytes use the CD44 class of molecules not only for binding to HEV at the site of lymphocyte entry to lymphoid organs as reported earlier but also within the lymphatic tissue where CD44, especially the subset modified by chondroitin sulfate, is used for interaction with extracellular matrix molecules such as fibronectin.

Amino Acid Sequence↗
PubMed1992

Expression of syndecan in transformed mouse keratinocytes.

BACKGROUND: Malignant transformation is frequently associated with altered behavior of cells, a phenomenon that also suggests changes in cell-matrix interactions. We have studied expression of syndecan, a cell surface proteoglycan that binds extracellular matrix components and growth factors, in various chemically transformed mouse keratinocyte cell lines that differ in their morphology and tumorigenicity. EXPERIMENTAL DESIGN: A monoclonal antibody, specific for mouse syndecan, and a cDNA clone for mouse syndecan, were used to detect syndecan in seven different keratinocyte cell lines. The glycosaminoglycan composition of syndecan was studied using differential digestions of heparan sulfate and chondroitin sulfate chains. RESULTS: In general, the tumorigenic cells were found to express lower amounts of syndecan, both at protein and mRNA levels, than the nontumorigenic cells. The most tumorigenic cell line CarC revealed barely detectable syndecan expression. Also, molecular polymorphism of syndecan was observed, as three forms of syndecan with different molecular weights appeared on the surfaces of different keratinocytes. The highly tumorigenic cells, that expressed low amounts of syndecan, expressed syndecan with the largest molecular weight. The different molecular weights were shown to reflect an increased amount of both heparan and chondroitin sulfate chains attached to the core protein. An increased shedding of syndecan ectodomain from the membrane-associated domain was observed in cells that express high amounts of mutated Ha-ras p21. CONCLUSIONS: The results suggest, that transformed epithelial cells can modulate the appearance of syndecan on the cell-surface by at least two ways: (a) by altering its glycosylation or (b) by increasing its shedding from the cell surface. These modulations, together with overall suppression of syndecan expression, could be associated with malignant transformation of keratinocytes.

Animals↗
PubMed1992

Syndecan in carcinomas produced from transformed epithelial cells in nude mice.

Expression of syndecan, a cell surface proteoglycan, was studied in carcinomas induced by implanting chemically transformed keratinocytes and mammary epithelial cells into nude mice. By immunohistochemistry and in situ hybridization, syndecan was localized in keratinizing cells within moderate- to well-differentiated squamous cell carcinomas in a pattern resembling that of normal epidermis, whereas almost total loss of expression was detected in poorly-differentiated areas within these tumors. In anaplastic spindle cell carcinomas, syndecan expression was barely detectable. In biphasic tumors, induced by mammary epithelial cells, and consisting of cysts overlaying an adenocarcinoma, syndecan was unquely localized to differentiated epithelial structures such as secretory epithelial lining of the cysts as well as aberrant glands and ducts within the carcinoma. Based on the expression pattern of syndecan in the tumors studied, we conclude that the expression of this developmentally regulated molecule is associated with epithelial differentiation also during neoplastic growth.

Animals↗
PubMed1991

Syndecan from embryonic tooth mesenchyme binds tenascin.

Syndecan is a cell surface heparan sulfate-rich proteoglycan found on various epithelial cells but also in some embryonic mesenchymal tissues. We have immunoisolated syndecan from embryonic tooth mesenchyme that appeared as a 250-300-kDa molecule (Kav = 0.3 in Sepharose 4B), containing only heparan sulfate side chains (Mr = 35,000). Northern analysis of whole tooth germs and tooth mesenchymes also revealed high expression of syndecan mRNAs (2.6 and 3.4 kilobases). In the binding assay utilizing nitrocellulose as a solid phase to immobilize matrix molecules, syndecan immunoisolated from tooth mesenchyme revealed binding to tenascin, and this interaction was shown to be mediated via heparan sulfate side chains. In contrast, syndecan from mouse mammary epithelial cells showed only weak interaction with tenascin. We propose that syndecan and tenascin may represent interactions of a cell surface receptor and a matrix ligand involved in mesenchymal cell condensation and differentiation during early organogenesis.

Animals↗
PubMed1991

Expression of syndecan gene is induced early, is transient, and correlates with changes in mesenchymal cell proliferation during tooth organogenesis.

Syndecan is an integral cell surface proteoglycan which contains an extracellular matrix-binding domain and a cytoskeleton-associated domain and may therefore transfer changes in the extracellular environment to cellular behavior. Changes in syndecan gene expression during embryonic and early postnatal mouse tooth development were analyzed by in situ hybridization and compared with the distribution of syndecan core protein and cell proliferation studied by immunohistochemistry. Syndecan RNA became accumulated in the condensing mesenchymal cells around the invaginating epithelial tooth bud during early development, and this accumulation became more intense when morphogenesis advanced to the cap stage. During the bell stage, when the cuspal pattern of the tooth is established, syndecan transcripts were lost, and RNA was not detected in the terminally differentiated or postmitotic odontoblasts. In the epithelium, syndecan RNA was intensely expressed in the invaginating epithelial bud, but the expression was reduced during the cap and bell stages. However, local stimulation in syndecan gene expression was observed in the epithelial preameloblasts immediately preceding their terminal differentiation into ameloblasts, which was accompanied by a complete loss of transcripts. There was a close correlation between the changes in syndecan transcripts and the distribution of syndecan core protein. Furthermore, analysis of cell proliferation by immunohistochemical detection of BrdU incorporation revealed that in the mesenchyme, but not in the epithelium, syndecan was intensely expressed by proliferating cells. The analysis of mRNA by Northern blot indicated that the transcripts in mesenchymal and epithelial cells were of similar size. In the slot-blot analysis the changes in syndecan transcripts correlated with the overall changes observed in the in situ hybridization analysis. The role of tissue interactions in the regulation of the syndecan gene was studied by using tissue recombination cultures of separated epithelial and mesenchymal components of the early tooth germ. The in situ hybridization and Northern blot analysis of these explants showed that the expression was increased in the mesenchyme cultured in contact with the epithelium. Our results indicate that syndecan gene expression in the embryonic tooth mesenchyme is induced by epithelial-mesenchymal interactions and thereafter expressed stage-dependently and transiently by the differentiating cells during organogenesis. The association of syndecan expression with mesenchymal cell proliferation raises the possibility that, in addition to behaving as a matrix receptor, syndecan may have a role in controlling growth and that syndecan may have different functions in epithelial and mesenchymal cells.

Animals↗
PubMed1991

Induced expression of syndecan in healing wounds.

We have studied the expression of an integral cell surface proteoglycan, syndecan, during the healing of cutaneous wounds, using immunohistochemical and in situ hybridization methods. In normal mouse skin, both syndecan antigen and mRNA were found to be expressed exclusively by epidermal and hair follicle cells. After incision and subsequent suturing, remarkably increased amounts of syndecan on the cell surfaces of migrating and proliferating epidermal cells and on hair follicle cells adjacent to wound margins were noted. This increased syndecan expression was shown to be a consequence of greater amounts of syndecan mRNA. Induction was observed already 1 d after wounding, was most significant at the time of intense cell proliferation, and was still observable 14 d after incision. The migrating cells of the leading edge of the epithelium also showed enhanced syndecan expression, although clearly less than that seen in the proliferating epithelium. The merging epithelial cells at the site of incision showed little or no syndecan expression; increased syndecan expression, however, was detected during later epithelial stratification. When wounds were left unsutured, in situ hybridization experiments also revealed scattered syndecan-positive signals in the granulation tissue near the migrating epidermal sheet. By immunohistochemical analysis, positive staining in granulation tissue was observed around vascular endothelial cells in a subpopulation of growing capillaries. Induction of syndecan in granulation tissue both at the protein and mRNA levels was temporally and spatially highly restricted. Granulation tissue, which formed in viscose cellulose sponge cylinders placed under the skin of rats, was also found to produce 3.4 and 2.6 kb mRNA species of syndecan similar to that observed in the normal murine mammary epithelial cell line, NMuMG. These results suggest that syndecan may have a unique and important role as a cell adhesion and a growth factor-binding molecule not only during embryogenesis but also during tissue regeneration in mature tissues.

Animals↗
PubMed1991

Steroid-induced epithelial-fibroblastic conversion associated with syndecan suppression in S115 mouse mammary tumor cells.

Cell-matrix interactions play an important role in the maintenance of cell shape, supposed to be mediated by the anchorage of cellular cytoskeleton to extracellular matrix via matrix receptors. In this work the expression of one of the known matrix receptors, syndecan, was studied during the hormone-induced change in the phenotype of Shionogi 115 (S115) mouse mammary tumor cells. In the presence of testosterone, when S115 cells express fibroblastic phenotype, they increased their growth rate and became gradually anchorage independent. These cells, however, revealed strong RGDS-dependent binding to fibronectin (FN) but not binding to the heparin-binding domain of FN. Instead, S115 cells growth without testosterone showed epithelial morphology and binding to the heparin-binding domain of FN, suggesting an alteration of syndecan expression in hormone-treated S115 cells. As quantitated by radioimmunoassay and by Western blot, the amounts of both matrix-binding ectodomain of syndecan and syndecan mRNA (2.6 kb) declined in hormone-treated S115 cells. The addition of antiandrogen cyproterone acetate to culture medium opposed the effect of testosterone on syndecan mRNA. We thus propose that the inactivation of syndecan gene and the consequent suppression of syndecan expression is related to the altered adhesion properties, the disappearance of epithelial phenotype, and, on the other hand, to the appearance of transformed-like phenotype in hormone-treated S115 cells.

Animals↗
PubMed1991

Immunohistochemical localization of syndecan in mouse skin tumors induced by UV irradiation. Loss of expression associated with malignant transformation.

Immunoreactivity for syndecan, a cell surface proteoglycan, which binds extracellular matrix molecules and growth factors, was studied in hairless (hr/hr) mice exposed to UV-A and UV-B irradiation. Positive staining was observed at the surface of normal epidermal cells as well as in the dermal abortive hair follicle cysts characteristic to this mouse strain. Early reaction to UV-irradiation showing hyperplastic epidermis with slight cellular atypia showed also positive, although reduced, staining of epidermal cell surfaces. Specimens with severe dysplasia showed weak staining in the granular cell layer, whereas the basal cell layer was negative. In papillomas and keratoacanthomas, immunoreactivity for syndecan was observed in the benign hyperplastic epidermal cells as well as in the proliferating epidermal cells of the horn cysts. Malignant transformation of epithelium, expressed as the formation of early invasive and anaplastic squamous cell carcinomas, was uniformly associated with loss of syndecan staining. These results are consistent with the previous findings of reduced expression of syndecan associated with malignant transformation of cultured epithelial cells, but also suggest an important role for syndecan in the maintenance of normal tissue architecture and differentiation pattern of the skin.

Animals↗
PubMed1990

Binding of human syndecan to extracellular matrix proteins.

We have isolated a cell surface proteoglycan from a human mammary cell line (HBL-100). This proteoglycan was found to be a human equivalent to mouse syndecan, because (i) it has identical biochemical properties with murine syndecan, including size, charge, buoyant density, and glycosaminoglycan composition, (ii) its core protein has identical size with murine syndecan as studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and (iii) the core protein is detected with anti-peptide antibody for the cytoplasmic domain of syndecan. HBL-100 cells also showed high expression of syndecan mRNAs, when probed with mouse syndecan cDNA. The ectodomain of the human syndecan revealed binding to type I collagen fibrils and fibronectin but not to laminin, duplicating the binding properties of murine syndecan. Very interestingly, syndecan did not bind to vitronectin, which is known to contain a heparin binding domain and is one of the major adhesive factors of serum for cultured cells. Syndecans are known to change their glycosaminoglycan composition yielding tissue-type specific polymorphic forms of syndecan (Sanderson, R., and Bernfield, M. (1988) Proc. Natl. Acad. Sci. U. S.A. 85, 9562-9566). The members of this family may thus represent a collection of structurally related matrix receptors that could differ in their interactions due to variation of the ectodomain glycosylation.

Blood Proteins↗
PubMed1990

Sequence of human syndecan indicates a novel gene family of integral membrane proteoglycans.

The structure of human syndecan, an integral membrane proteoglycan, has been determined by cloning its full-length cDNA, which codes for the entire 310-amino acid-long core protein, including the NH2-terminal signal peptide. Similar to mouse syndecan (Saunders, S., Jalkanen, M., O'Farrell, S., and Bernfield, M. (1989) J. Cell Biol. 108, 1547-1556), the core protein of human syndecan can be divided into three domains: a matrix-interacting ectodomain containing putative glycosaminoglycan attachment sites, a 25-residue hydrophobic membrane-spanning domain, and a 34-residue cytoplasmic domain. Several interesting conserved structures were revealed by comparing the human syndecan sequence to the murine one. (i) Although the ectodomains are only 70% identical, all putative glycosaminoglycan attachment sites are identical (two of them belong to the consensus sequence SGXG and three others to (E/D)GSG(E/D), as are also (ii) the single putative N-glycosylation site and (iii) the proteinase-sensitive dibasic RK site adjacent to the extracellular face of the transmembrane domain. Furthermore, (iv) the transmembrane domain is 96% identical, as the only change in human syndecan was an alteration of an alanine residue to glycine; and finally, (v) the cytoplasmic domain is 100% identical, including 3 identically located tyrosine residues. Comparison of transmembrane and cytoplasmic domains to a third cell-surface proteoglycan, 48K5 from human lung fibroblasts (Marynen, P., Zhang, J., Cassiman, J., Vanden Berghe, H., and David, C. (1989) J. Biol. Chem. 264, 7017-7024), indicates that the transmembrane and cytoplasmic domains are similar also in this molecule regardless of the presence of a totally nonhomologous ectodomain. Thus, the transmembrane and cytoplasmic domains are unique for these cell-surface proteoglycans, which we propose to be members of a novel gene family of syndecans.

Amino Acid Sequence↗
PubMed1990

Localization of gene for human syndecan, an integral membrane proteoglycan and a matrix receptor, to chromosome 2.

Syndecan, a cell surface proteoglycan, is an integral membrane protein acting as a receptor for the extracellular matrix. For chromosomal localization of the human syndecan gene, a panel of mouse-human somatic cell hybrids was analyzed by Southern blotting using the cDNA probe for human syndecan. The hybrids were karyotyped at the time of DNA extraction. A band corresponding to the human syndecan gene in Southern blots was found only in a hybrid cell line containing human chromosome 2. This hybrid was subcloned and its subclones were analyzed by Southern blotting and karyotyped. Subclones carrying human chromosome 2 contained the syndecan gene, while subclones not carrying this chromosome did not. The human syndecan gene is thus assigned to chromosome 2.

Animals↗
PubMed1989

Epithelial-mesenchymal interactions regulate the stage-specific expression of a cell surface proteoglycan, syndecan, in the developing kidney.

Morphogenesis of the kidney is regulated by reciprocal tissue interactions between the epithelial ureter bud and the metanephric mesenchyme. The differentiation of the kidney involves profound changes in the extracellular matrix, and therefore matrix receptors may have an important role in this process. We studied the expression of syndecan, a cell surface proteoglycan acting as a receptor for interstitial matrix materials, by using a monoclonal antibody against the core protein of the molecule. Syndecan was not detected in the uninduced metanephric mesenchyme. During the formation of the ureter bud from the Wolffian duct, syndecan appeared in the mesenchymal cells around the invaginating bud. Simultaneously with the first branching of the ureter bud, the whole nephric mesenchyme became syndecan positive, but a 3- to 10-cell-thick layer around the branching ureter bud, representing the presumptive tubular cells, was most intensely stained. During the assembly of the mesenchyme cells into pretubular aggregates, syndecan was detected in these aggregates and, to a lesser degree, in the morphologically undifferentiated mesenchyme. Thereafter syndecan was found only in the differentiating epithelium, from which it was gradually lost during maturation of the nephron. It was last detected in the periphery of the kidney, where tubulogenesis still continued. In transfilter cultures we showed that syndecan appeared in the nephric mesenchyme during the period when the mesenchyme becomes programmed to transform into epithelial structures. By using interspecies recombinations and a species-specific antibody we excluded the possibility that syndecan in the mesenchyme would originate from the inductor. We conclude that syndecan expression is regulated by epithelial-mesenchymal interactions. The findings that syndecan appeared as an early response to induction and that its distribution showed both spatial and temporal correlation with kidney morphogenesis suggest an important role for this molecule in development.

Animals↗
PubMed1989

The testes of moles (Talpa europaea) retain a considerable microsomal capacity for androgen synthesis during seasonal regression.

Seasonal changes in testicular histology and steroidogenesis were investigated in the mole (Talpa europaea). Androgen synthesis was examined by incubating [4-14C]pregnenolone (P) and [4-14C]dehydroepiandrosterone (DHA) with testicular minces in a static incubation system. The metabolites formed were characterized by thin-layer chromatography. Morphological changes were studied by routine histological methods. During sexual quiescence spermatogenesis was arrested. The regressive seminiferous tubules consisted predominantly of Sertoli cells and spermatogonia. On the other hand, histological quantification suggested that season has no significant effects on the number or the nuclear dimensions of Leydig cells in this species. The capacity of the regressive testes (per unit weight) to metabolize P and DHA to testosterone (T) was somewhat greater in regressive (48.5%, 49.4%) than in active (33.2%, 41.6%) testes. The results also suggest that the greater in vitro T production encountered during reproductive quiescence is due possibly to an increase in the activity of 17 beta-hydroxysteroid dehydrogenase (per unit weight). Our data on Leydig cell numbers indicate, however, that the capacity of the individual Leydig cells to produce T is decreased during sexual regression. T. europaea appears to be quite exceptional among seasonally breeding small mammals exhibiting pronounced annual changes in spermatogenesis in that the testes retain a considerable enzymatic capacity to produce testosterone from pregnanes during sexual quiescence. The results suggest that pituitary as well as paracrine regulation of the annual testicular cycle in this species differs from that generally encountered in seasonal breeders.

Androgens↗
PubMed1989

Molecular cloning of syndecan, an integral membrane proteoglycan.

We describe cDNA clones for a cell surface proteoglycan that bears both heparan sulfate and chondroitin sulfate and that links the cytoskeleton to the interstitial matrix. The cDNA encodes a unique core protein of 32,868 D that contains several structural features consistent with its role as a glycosamino-glycan-containing matrix anchor. The sequence shows discrete cytoplasmic, transmembrane, and NH2-terminal extracellular domains, indicating that the molecule is a type I integral membrane protein. The cytoplasmic domain is small and similar in size but not in sequence to that of the beta-chain of various integrins. The extracellular domain contains a single dibasic sequence adjacent to the extracellular face of the transmembrane domain, potentially serving as the protease-susceptible site involved in release of this domain from the cell surface. The extracellular domain contains two distinct types of putative glycosaminoglycan attachment sites; one type shows sequence characteristics of the sites previously described for chondroitin sulfate attachment (Bourdon, M. A., T. Krusius, S. Campbell, N. B. Schwartz, and E. Ruoslahti. 1987. Proc. Natl. Acad. Sci. USA. 84:3194-3198), but the other type has newly identified sequence characteristics that potentially correspond to heparan sulfate attachment sites. The single N-linked sugar recognition sequence is within the putative chondroitin sulfate attachment sequence, suggesting asparagine glycosylation as a mechanism for regulating chondroitin sulfate chain addition. Both 5' and 3' regions of this cDNA have sequences substantially identical to analogous regions of the human insulin receptor cDNA: a 99-bp region spanning the 5' untranslated and initial coding sequences is 67% identical and a 35-bp region in the 3' untranslated region is 81% identical in sequence. mRNA expression is tissue specific; various epithelial tissues show the same two sizes of mRNA (2.6 and 3.4 kb); in the same relative abundance (3:1), the cerebrum shows a single 4.5-kb mRNA. This core protein cDNA describes a new class of molecule, an integral membrane proteoglycan, that we propose to name syndecan (from the Greek syndein, to bind together).

Amino Acid Sequence↗