Biomedical subjects

K Takio

Publications and source records attributed to K Takio.

At least 109 records · Page 6Linked to original sources

PubMed1991

Neural cell adhesion molecule mediates contact-dependent inhibition of growth of near-diploid mouse fibroblast cell line m5S/1M.

A near-diploid mouse fibroblast cell line m5S/1M used in this study shows a high sensitivity to contact-dependent inhibition of growth, and the addition of EGF causes both morphological change and loss of contact-dependent inhibition of growth. The m5S/1M cell and its transformants obtained by x-ray irradiation have been used to search for the cell surface glycoproteins that are responsible for the growth regulation via cell-cell interactions. Lectin blotting analyses showed that the expression of the cell surface glycoprotein of 140 kD (140KGP) is highly sensitive to the transformation induced either by x-ray irradiation or by the EGF stimulation. We purified the 140KGP and found that it was composed of two glycoproteins. The major component of 140KGP was identified as neural cell adhesion molecule (NCAM) by amino acid sequence analyses of the peptide fragments and by the cross-reactivity with anti-NCAM mAb, clone H28.1.2.3. Monoclonal antibody against 140KGP (clone LN-10) recognizes all three isoforms of NCAM expressed on m5S/1M cell and showed that the expression of NCAM was highly sensitive to the transformation. Furthermore, the immobilized LN-10 strongly inhibited the growth of actively proliferating m5S/1M cells and the LN-10 in a soluble form showed a significant growth-stimulating effect on the confluent quiescent cultures of m5S/1M cells. The results show that NCAM plays a major role in the contact-dependent inhibition of growth of m5S/1M, and that NCAM might be involved in the regulation of cell growth during embryogenesis and formation of nervous systems.

Amino Acid Sequence↗

PubMed1991

Activin-binding protein is present in pituitary.

A binding protein for activin was purified from bovine pituitary by affinity chromatography on dextran sulfate-Sepharose CL-4B and activin-Affi-Gel 10. A 52,700-fold purification over the starting crude homogenate was achieved. The purified preparation showed two bands of 36 and 33 kilodalton in sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions. The ability of each form of the protein to specifically bind activin was determined by ligand blot analysis and binding competition study. Each protein was found to have the same NH2-terminus and its sequence was identical to that of follistatin, which is a specific inhibitor of identical to that of follistatin, which is a specific inhibitor of FSH release. Moreover, the binding protein was shown to inhibit the spontaneous FSH release from cultured pituitary cells as does follistatin. These properties are the same as activin-binding protein that we have obtained from rat ovary. These results support a conclusion that activin-binding protein/follistatin exists also in the pituitary. Activin-binding protein has an ability to inhibit the activin-induced augmentation of FSH release from cultured pituitary cells as does inhibin. However, the inhibitory pattern by the binding protein was quite distinct from that of inhibin, suggesting that there may be different mechanism(s) for their antagonistic actions. Stoichiometric inhibition as shown by gel filtration analysis indicates that activin-binding protein binds activin to form an inactive equimolar complex having neither stimulatory nor inhibitory activity for FSH secretion by the pituitary. These findings suggest that activin is actually involved in FSH secretion in the pituitary and that the activin action in the pituitary is regulated by activin-binding protein/follistatin.

Activins↗

PubMed1990

Isolation and characterization of human cDNA clones encoding the alpha and the alpha' subunits of casein kinase II.

Casein kinase II is a widely distributed protein serine/threonine kinase. The holoenzyme appears to be a tetramer, containing two alpha or alpha' subunits (or one of each) and two beta subunits. Complementary DNA clones encoding the subunits of casein kinase II were isolated from a human T-cell lambda gt10 library using cDNA clones isolated from Drosophila melanogaster [Saxena et al. (1987) Mol. Cell. Biol. 7, 3409-3417]. One of the human cDNA clones (hT4.1) was 2.2 kb long, including a coding region of 1176 bp preceded by 156 bp (5' untranslated region) and followed by 871 bp (3' untranslated region). The hT4.1 clone was nearly identical in size and sequence with a cDNA clone from HepG2 human hepatoma cultured cells [Meisner et al. (1989) Biochemistry 28, 4072-4076]. Another of the human T-cell cDNA clones (hT9.1) was 1.8 kb long, containing a coding region of 1053 bp preceded by 171 bp (5' untranslated region) and followed by 550 bp (3' untranslated region). Amino acid sequences deduced from these two cDNA clones were about 85% identical. Most of the difference between the two encoded polypeptides was in the carboxy-terminal region, but heterogeneity was distributed throughout the molecules. Partial amino acid sequence was determined in a mixture of alpha and alpha' subunits from bovine lung casein kinase II. The bovine sequences aligned with the 2 human cDNA-encoded polypeptides with only 2 discrepancies out of 535 amino acid positions. This confirmed that the two human T-cell cDNA clones encoded the alpha and alpha' subunits of casein kinase II. Microsequence data determined from separated preparations of bovine casein kinase II alpha subunit and alpha' subunit [Litchfield et al. (1990) J. Biol. Chem. 265, 7638-7644] confirmed that hT4.1 encoded the alpha subunit and hT9.1 encoded the alpha' subunit. These studies show that there are two distinct catalytic subunits for casein kinase II (alpha and alpha') and that the sequence of these subunits is largely conserved between the bovine and the human.

Amino Acid Sequence↗

PubMed1990

Structure of a mouse immunoglobulin G that lacks the entire CH1 domain: protein sequencing and small-angle X-ray scattering studies.

The structure of a short-chain IgG2a antibody, which is a member of the family of mouse anti-dansyl switch variant antibodies with identical variable regions but different heavy-chain constant regions [Dangl, J.L., Parks, D. R., Oi, V. T., & Herzenberg, L. A. (1982) Cytometry 2, 395-401], is reported. Amino acid sequencing analyses have demonstrated that in the short-chain IgG2a antibody the entire CH1 domain is deleted whereas the hinge region remains intact. Small-angle X-ray scattering data were collected for the short-chain IgG2a antibody and compared with those for the switch variant IgG1, IgG2a, and IgG2b antibodies with the normal heavy chain. It has been concluded that deletion of the CH1 domain results in a large structural change and the short-chain IgG2a antibody possesses an elongated molecular shape with a much smaller hinge angle as compared with the normal IgG2a antibody that is a Y-shaped molecule.

Amino Acid Sequence↗

PubMed1990

Subunit structure of casein kinase II from bovine testis. Demonstration that the alpha and alpha' subunits are distinct polypeptides.

The relationship between the alpha and alpha' subunits of casein kinase II was studied. For this study, a rapid scheme for the purification of the enzyme from bovine testis was developed. Using a combination of chromatography on DEAE-cellulose, phosphocellulose, hydroxylapatite, gel filtration on Sephacryl S-300 and heparin-agarose, the enzyme was purified approximately 7,000-fold. The purification scheme was completed within 48 h and resulted in the purification of milligram quantities of casein kinase II from 1 kg of fresh bovine testis. The purified enzyme had high specific activity (3,000-5,000 nmol of phosphate transferred per min/mg protein) when assayed at 30 degrees C with ATP and the synthetic peptide RRRDDDSDDD as substrates. The isolated enzyme was a phosphoprotein with an alkali-labile phosphate content exceeding 2 mol/mol protein. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis three polypeptides were apparent: alpha (Mr 45,000), alpha' (Mr 40,000), and beta (Mr 26,000). Several lines of evidence conclusively demonstrated that the alpha and alpha' subunits are distinct polypeptides. Two-dimensional maps of 125I-tryptic peptides derived from the two proteins were related, but distinct. An antipeptide antibody was raised in rabbits which reacted only with the alpha subunit on immunoblots and failed to react with either the alpha' or beta subunits. Direct comparison of peptide sequences obtained from the alpha and alpha' subunits revealed differences between the two polypeptides. The results of this study clearly demonstrate that the alpha and alpha' subunits of casein kinase II are not related by post-translational modification and are probably encoded by different genes.

Amino Acid Sequence↗

PubMed1990

Characterization through cDNA cloning of galactoprotein b3 (Gap b3), a cell surface membrane glycoprotein showing enhanced expression on oncogenic transformation. Identification of Gap b3 as a member of the integrin superfamily.

Galactoprotein b (Gap b) is a group of glycoproteins of fibroblast cell membranes showing enhanced expression in association with oncogenic transformation (Carter, W.G., and Hakomori, S. (1977) Biochem. Biophys. Res. Commun. 76, 299-308). We purified Gap b3 (one of the Gap b group) to homogeneity from hamster fibroblast NIL cells transformed with polyoma virus (NILpy). Partial amino acid sequence was determined, and the cDNA clones encoding this protein were isolated by oligodeoxynucleotide hybridization. The 5.0-kilobase pair cDNA encodes a protein of 1051 amino acid residues containing a signal peptide (32 residues), a large extracellular domain (959 residues), a transmembrane domain (28 residues), and a short cytoplasmic domain (32 residues). The overall structure of Gap b3 is similar to that of the alpha subunit of so-called integrin receptors in the following respects: (i) presence of metal-binding sequences; (ii) location of a transmembrane domain near C terminus; (iii) matched positions of most of the cysteine residues. This, together with extensive amino acid sequence homology, strongly suggests that Gap b3 is a member of the integrin family. Gap b3 consists of two polypeptide chains (Mr = 110,000 and 30,000), which seem to be proteolytic cleavage products connected by disulfide bonds from a precursor protein. Southern hybridization shows the presence of a single copy gene in mice and humans as well. Northern hybridization analysis shows that the enhanced expression of Gap b3 in transformed cells is due to increased transcription of its message.

Amino Acid Sequence↗

PubMed1990

Activin-binding protein from rat ovary is follistatin.

Activin, a member of the transforming growth factor beta protein family, was originally isolated from gonadal fluids and stimulates the release of pituitary follicle-stimulating hormone (FSH). Activin has numerous functions in both normal and neoplastic cells. Various cells synthesize activin and have a specific binding site for this peptide. However, the molecular basis for its actions is unknown. A binding protein for activin was purified from rat ovary and was identical to follistatin, a specific inhibitor of FSH release. It is likely that the binding protein participates in the diverse regulatory actions of activin.

Activins↗

PubMed1990

Isolation to homogeneity and partial characterization of a histo-blood group A defined Fuc alpha 1----2Gal alpha 1----3-N-acetylgalactosaminyltransferase from human lung tissue.

The soluble histo-blood group A glycosyltransferase (Fuc alpha 1----Gal alpha 1----3-N-acetylgalactosaminyltransferase) was purified approximately 600,000-fold to homogeneity from human lung tissue. The enzyme was solubilized in 1% Triton X-100, partially purified by affinity chromatography on Sepharose 4B, and eluted with UDP. Final purification was obtained by twice repeated fast protein liquid chromatography ion exchange (Mono STM) with NaCl gradient elution and reverse-phase chromatography (proRPC) with acetonitrile gradient elution. Identity of the purified protein was established by (i) demonstration of the putative A transferase protein only in affinity-purified extracts of A but not O individuals, and (ii) specific immunoprecipitation of enzyme activity and putative protein with monoclonal antibodies. Sodium dodecyl sulfate electrophoresis revealed a single protein band with apparent Mr of approximately 40,000 under both reducing and nonreducing conditions. Digestion with N-glycanase yielded a reduction in Mr of approximately 6,000 (estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis), suggesting that the A transferase is a glycoprotein with N-linked carbohydrate chains. Amino acid composition and N-terminal amino acid sequence of the intact transferase, as well as of peptides released by endolysyl peptidase digest or cyanogen bromide cleavage, are presented.

ABO Blood-Group System↗

PubMed1989

Identification of beta protein precursor in newborn rat brain.

We have identified by protein sequencing the precursor of beta protein in newborn rat brain. A rabbit antibody was raised against a synthetic peptide corresponding to the carboxyl-terminal 30 residues (666-695) of the putative beta-amyloid protein precursor (Kang et al. 1987). The antiserum recognized multiple bands at 110-130 kD in the blot of Triton X-100 extract of newborn rat brain homogenates. The partially purified immunoreactive proteins were subjected to SDS-PAGE, electrophoretically transferred onto a polyvinylidene difluoride membrane and analyzed for the partial amino-terminal sequence. Each of the three major immunoreactive polypeptides yielded the same amino-terminal sequence of LEVPTxGNAgxL (x: unidentified, g: weakly assigned glycine) which corresponds to the residues 18-29 of the putative precursor.

Alzheimer Disease↗

PubMed1989

Inhibin alpha-subunit monomer is present in bovine follicular fluid.

The 26 kDa form of the inhibin alpha-subunit monomer was isolated from bovine follicular fluid. Both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting analysis revealed that the 26 kDa form of the alpha-subunit monomer is composed of 6 kDa and 20 kDa fragments linked together by a disulfide bond(s). The NH2-terminal sequence and amino acid analyses of each fragment showed that those fragments are derived from residues 18 to 60 and 227 to 360, respectively, of the inhibin alpha-subunit precursor (residues 1 to 360) as deduced from the cDNA sequence. Thus, it is concluded that removal of the putative signal peptide (residues 1 to 17) and the middle portion (residues 61 to 226) from the alpha-subunit precursor generates the 26 kDa form of the alpha-subunit. In the in vitro rat pituitary assay, the 26 kDa alpha-subunit exhibited neither inhibin-like nor FSH-release stimulating activity.

Amino Acid Sequence↗

PubMed1989

N-terminal sequencing of photosystem II low-molecular-mass proteins. 5 and 4.1 kDa components of the O2-evolving core complex from higher plants.

High resolution gel electrophoresis in the low-molecular-mass region combined with electroblotting using polyvinylidene difluoride membranes enabled us to sequence the low-molecular-mass proteins of photosystem II membrane fragments from spinach and wheat. The determined N-terminal sequences, all showing considerable homology between the two plants, involved two newly determined sequences for the 4.1 kDa protein and one for the 5 kDa proteins. The sequence of the 4.1 kDa protein did not match any part of the chloroplast DNA sequence from tobacco or liverwort, suggesting that it is encoded by the nuclear genome. In contrast, the sequence of the 5 kDa protein matched ORF38, which is located just downstream of psbE and psbF in the chloroplast DNA and is assumed to be co-transcribed with them. These two components were associated with the O2-evolving core complex. Sequences of other low-molecular-mass proteins confirmed the previous identification as photosystem II components.

Amino Acid Sequence↗

PubMed1989

Reevaluation of the amino acid sequence of porcine follitropin.

We have reevaluated the sequence of porcine follicle-stimulating hormone (pFSH) with more recent protein-sequencing methodology. This has led to revision of the earlier proposed sequence. As with almost all reported gonadotropin alpha-subunits, NH2-terminal heterogeneity was found in the porcine FSH alpha-subunit (FSH alpha), starting with residue Phe (1), Asp (3), Gly (4), or Thr (7). In the beta-subunit, there were found to be at least two molecular species, starting with residue Asn (1) (minor 20%) or Cys (3) (major 80%) as NH2-terminal and ending at residue Glu (108) as COOH-terminal. The net effect of the present revisions is to increase the homology of pFSH beta with other reported follitropin sequences. Apparent differences in the half-cystine placements in a previous proposal for pFSH beta compared with other species of FSH are no longer tenable. The half-cystine placements thus remain a constant structural feature throughout the gonadotropin hormones (choriogonadotropin, follitropin, and lutropin).

Amino Acid Sequence↗

PubMed1988

Homology of perforin to the ninth component of complement (C9).

Perforin is one of the cytolytic factors present in the cytoplasmic granules of mouse cytotoxic T lymphocytes and natural killer cells. We have determined the sequence of the N-terminal amino acids of perforin purified from a mouse natural killer cell line, and, by using oligonucleotide probes corresponding to the amino acid residues, we have identified a complementary DNA encoding perforin from the cDNA library of a mouse cytotoxic T lymphocyte clone. As predicted from the functional similarities between perforin and the ninth component of the serum cytolytic system, complement (C9) (refs 4-8), the deduced primary structure of perforin has homology with C9 at their respective functionally conserved regions. We find that perforin is only expressed in killer cell lines, and not in helper T lymphocytes or other tumour cells tested. Thus we have provided direct molecular evidence that a killer-cell-specific protein evolutionally linked to C9 is involved in cell-mediated cytolysis.

Amino Acid Sequence↗

PubMed1988

The oncofetal structure of human fibronectin defined by monoclonal antibody FDC-6. Unique structural requirement for the antigenic specificity provided by a glycosylhexapeptide.

Previously, monoclonal antibody FDC-6 was established, which defines a structure specific for fibronectins isolated from fetal and malignant cells and tissues. The presence of the FDC-6-defined structure at type III connecting segment (III CS) is characteristic of oncofetal fibronectin (onf-FN), and its absence is characteristic of normal fibronectin (nor-FN) (Matsuura, H., and Hakomori, S. (1985) Proc. Natl. Acad. Sci. U. S. A. 82, 6517-6521). Hepatoma fibronectin was sequentially digested by various proteases, followed by subsequent chromatography on an FDC-6 affinity column and reverse-phase columns at each step of digestion. A single strongly active glycosylhexapeptide (glycopeptide 1) and an inactive glycosylpentapeptide (glycopeptide 3) were isolated from glycopeptide A containing 35 amino acid residues. The minimum essential structure required for the FDC-6 activity was found to be a hexapeptide sequence Val-Thr-His-Pro-Gly-Tyr having NeuAc alpha 2----3Gal beta 1----3GalNAc or its core (Gal beta 1----3GalNAc or GalNAc) linked at threonine. Various synthetic peptides including the Val-Thr-His-Pro-Gly-Tyr sequence and a glycopeptide having the Val-Thr-His-Pro-Gly pentapeptide with the same glycosylation at threonine were all inactive. Elimination of sialic acid slightly increased the activity, and subsequent elimination of galactose did not alter the activity; however, removal of the Gal beta 1----3GalNAc residue by endo-alpha-N-acetylgalactosaminidase from desialylated glycopeptide A resulted in total inactivation of the reactivity with FDC-6 antibody. Thus, a single glycosylation at a defined threonine residue of the III CS region may induce conformational changes in the peptide to form the specific oncofetal epitope recognized by FDC-6 antibody. This finding opens the possibility that a number of other oncofetal epitopes consist of a peptide and a common O-linked carbohydrate and that the combination produces a conformation specific to cancer or to a stage of development.

Amino Acid Sequence↗

PubMed1987

Microanalysis of the amino acid sequence of the eclosion hormone from the tobacco hornworm Manduca sexta.

The amino acid sequence of the eclosion hormone from the tobacco hornworm Manduca sexta has been determined, using less than 500 pmol of protein and microanalytical techniques. The protein contains 62 amino acid residues and has a molecular mass of 6813 Da. The amino-terminal sequence is similar to that of a 13-residue segment at the amino terminus of the eclosion hormone of the silkworm Bombyx mori, but the hormone is not otherwise homologous with other hormones or proteins.

Amino Acid Sequence↗

PubMed1987

Amino acid sequence of sialic acid binding lectin from frog (Rana catesbeiana) eggs.

The complete amino acid sequence of sialic acid binding lectin from frog (Rana catesbeiana) egg is presented. The 111-residue sequence was determined by the analysis of peptides generated by digestion of the S-carboxymethylated protein with Achromobacter protease I, chymotrypsin, or cyanogen bromide. The sequence is unique and not homologous to any known protein sequence. The protein may represent a new type of lectin.

Amino Acid Sequence↗

PubMed1987

Amino acid sequence of the beta subunit of bovine lung casein kinase II.

The amino acid sequence of the 209-residue beta subunit of bovine lung casein kinase II has been determined. Excluding the amino-terminal blocking group, which was not identified, the molecular weight of the polypeptide chain is 24,239. A marked polarity of the beta subunit is indicated by clusters of negative charges in the amino-terminal region and of positive charges in the carboxyl-terminal region. Whereas the beta subunit shows no homology with any known protein, a segment of the sequence of the larger and microheterogeneous alpha subunit exhibits homology with the catalytic domains of other protein kinases, particularly with the yeast cell-division-control protein CDC28.

Amino Acid Sequence↗

PubMed1987

Amino acid sequence of the von Willebrand factor-binding domain of platelet membrane glycoprotein Ib.

We report the amino acid sequence of a 299-residue segment from the alpha chain of the human platelet membrane glycoprotein Ib. This includes the complete sequence of the amino-terminal tryptic fragment of 290 residues comprising the von Willebrand factor-binding domain. Two primary sets of overlapping fragments were obtained by cleavage of the S-carboxymethylated protein at methionyl and lysyl bonds following treatment with cyanogen bromide and Achromobacter protease I, respectively. Additional fragments were obtained by treatment of native glycocalicin with trypsin, Staphylococcus aureus V8 protease, and Serratia marcescens protease. Analysis of all these fragments provided data that allowed determination of the continuous sequence corresponding to approximately half of the alpha-chain polypeptide. This region of glycoprotein Ib is largely hydrophobic and contains only two N-linked and one O-linked carbohydrate chains. A hydrophilic region exists between residues 215 and 299, which contains a cluster of 10 negatively charged residues at 269-287. This area is likely to attract positively charged molecules. The hydrophilic, highly glycosylated (at serine and threonine residues) region corresponding to the previously described "macroglycopeptide" and representing the carboxyl-terminal half of the alpha chain is likely to begin at residue 292. The determined sequence of the alpha chain of glycoprotein Ib contains a region (residues 29-193) with seven repeats, which is indicative of gene duplication and is highly homologous to human leucine-rich alpha 2-glycoprotein. This protein sequence agrees completely with that deduced from the cDNA sequence reported by Lopez et al. [Lopez, J.A., Chung, D.W., Fujikawa, K., Hagen, F.S., Papayannopoulou, T. & Roth, G.J. (1987) Proc. Natl. Acad. Sci. USA 84, 5615-5619].

Amino Acid Sequence↗