Biomedical subjects

P Böhlen

Publications and source records attributed to P Böhlen.

At least 19 recordsLinked to original sources

PubMed2001

Development of a high throughput screening assay for inhibitors of fibroblast growth factor-receptor-heparin interactions.

High throughput screening (HTS) of large compound libraries for inhibitors of growth factors raises the requirement for simple yet reliable assays. Fibroblast growth factors (FGFs) play a pivotal role in the multistep pathway of malignant transformation, tumor progression, metastasis, and angiogenesis. FGF-2 (basic FGF) requires a cooperative interaction with heparin or heparan sulfate proteoglycans in order to form functional growth factor-receptor complexes that are essential for receptor binding and activation. We have developed a simple screening system, devised to identify molecules that modulate heparin-FGF-receptor interactions. The system is composed of a heparin matrix, FGF-2, and a FGF receptor-1 protein engineered by genetically fusing the extracellular domain of FGF receptor-1 to alkaline phosphatase (FRAP). The screen is conducted using 96-well plates to which heparin has been covalently attached. FGF-2 is then bound to the plates through heparin-FGF interactions, followed by the addition of FRAP and compounds to be screened for modulation of heparin-FGF, receptor-heparin, and receptor-FGF interactions. The endpoint of the assay is measured enzymatically using the alkaline phosphatase (AP)-catalyzed formation of a chromogenic product, which is directly proportional to the amount of FRAP present on the plates as a heparin-FGF-FRAP ternary complex. Reduced AP values relative to control, as measured by spectrophotometry, indicate inhibition of the formation of an active FGF-receptor-heparin complex. The simple and versatile nature of the assay makes it an attractive HTS system. The screen has identified several potent inhibitors of FGF-2 receptor binding and activation. Furthermore, secondary screening of the HTS-recognized compounds identified several compounds that have the capacity to block growth factor-mediated tumor progression and angiogenesis in vivo.

Animals↗

PubMed1998

Monoclonal antibodies targeting the VEGF receptor-2 (Flk1/KDR) as an anti-angiogenic therapeutic strategy.

Biological evidence suggests that interference with the function of the angiogenic growth factor receptor VEGFR2 (flk1/KDR) is a particularly promising strategy to inhibit tumor-induced angiogenesis. Proof of concept was established by developing a monoclonal rat anti-mouse VEGFR2 antibody (DC101) and showing that it potently blocked the binding of VEGF to its receptor, inhibited VEGF-induced signaling, and strongly blocked tumor growth in mice through an anti-angiogenic mechanism. Since DC101 does not cross-react with the human VEGFR2 KDR, anti-KDR monoclonal antibodies were generated by standard hybridoma technology and by using phage display library. High affinity antibodies (Kd = 4.9 x 10(-10)-1.1 x 10(-9) M) were found with both approaches. The anti-KDR antibodies compete on an equimolar basis with VEGF for binding to KDR and inhibit with similar potency the VEGF-induced signaling and mitogenesis in human endothelial cells. Although these antibodies cannot be tested for in vivo efficacy in standard murine tumor models because of lack of species cross-reactivity, the similarity of their in vitro properties with those of DC101 suggests that they may be effective in blocking KDR function in vivo.

Animals↗

PubMed1997

Properly oriented heparin-decasaccharide-induced dimers are the biologically active form of basic fibroblast growth factor.

Interaction of basic fibroblast growth factor (FGF-2) with heparin or heparan sulfate proteoglycans (HSPGs) is required for receptor activation and initiation of biological responses. To gain insight into the mechanism of activation of the FGF receptor by FGF-2 and heparin, we have used NMR, dynamic light scattering, and HSPG-deficient cells and cell-free systems. The first 28 N-terminal residues in FGF-2 were found to be highly mobile and flexible, consistent with the disorder found in both the NMR and X-ray structures. The structure of an FGF-2-heparin-decasaccharide complex that binds to and activates the FGF receptor was compared to a heparin-tetrasaccharide-induced complex that does not promote an interaction with the receptor. The major change observed upon the addition of the tetrasaccharide to FGF-2 was an increase in the correlation time consistent with the formation of an FGF-2 dimer. The NMR line widths of FGF-2 in the presence of the decasaccharide are severely broadened relative to the tetrasaccharide, consistent with dynamic light scattering results which indicate FGF-2 is a tetramer. The interaction of these heparin species with FGF-2 does not induce a significant conformational change in the overall structure of FGF-2, but small chemical shift changes are observed in both heparin and receptor binding sites. A trans-oriented symmetric dimer of FGF-2 is formed in the presence of the tetrasaccharide whereas two cis-oriented dimers in a symmetric tetramer are formed in the presence of the decasaccharide. This suggests that the cis-oriented FGF-2 dimer is the minimal biologically active structural unit of FGF-2. These data allow us to propose a novel mechanism to explain the functional interaction of FGF-2 with heparin and its transmembrane receptor.

Animals↗

PubMed1996

High-resolution solution structure of basic fibroblast growth factor determined by multidimensional heteronuclear magnetic resonance spectroscopy.

The high-resolution solution structure of recombinant human basic fibroblast growth factor (FGF-2), a protein of 17.2 kDa that exhibits a variety of functions related to cell growth and differentiation, has been determined using three-dimensional heteronuclear NMR spectroscopy. A total of 30 structures were calculated by means of hybrid distance geometry--simulated annealing using a total of 2865 experimental NMR restraints, consisting of 2486 approximate inteproton distance restraints, 50 distance restraints for 25 backbone hydrogen bonds, and 329 torsion angle restraints. The atomic rms distribution about the mean coordinate positions for the 30 structures for residues 29-152 is 0.43 +/- 0.03 A for the backbone atoms, 0.83 +/- 0.05 A for all atoms, and 0.51 +/- 0.04 A for all atoms excluding disordered side chains. The overall structure of FGF-2 consists of 11 extended antiparallel beta-strands arranged in three groups of three or four strands connected by tight turns and loop regions creating a pseudo-3-fold symmetry. Two strands from each group come together to form a beta-sheet barrel of six antiparallel beta-strands. A helix-like structure was observed for residues 131-136, which is part of the heparin binding site (residues 128-138). The discovery of the helix-like region in the primary heparin binding site instead of the beta-strand conformation described in the X-ray structures may have important implications in understanding the nature of heparin--FGF-2 interactions. A total of seven tightly bound water molecules were found in the FGF-2 structure, two of which are located in the heparin binding site. The first 28 N-terminal residues appear to be disordered, which is consistent with previous X-ray structures. A best fit superposition of the NMR structure of FGF-2 with the 1.9 A resolution X-ray structure by Zhu et al. (1991) yields a backbone atomic rms difference of 0.94 A, indicative of a close similarity between the NMR and X-ray structures.

Binding Sites↗

PubMed1995

Engineering of fibroblast growth factor: alteration of receptor binding specificity.

A five-residue loop structure in basic fibroblast growth factor (FGF-2) which extends from amino acid residue 118 to residue 122 was replaced, by cassette mutagenesis, with the corresponding seven-residue loop structure from the structural homologue acidic fibroblast growth factor (FGF-1) or the corresponding five-residue loop from interleukin-1 beta to give FGF-2LA and FGF-2LI, respectively. The mutants were expressed in Escherichia coli and purified to homogeneity, and their heparin and receptor binding and biological properties were examined. The ability of FGF-2LA to induce endothelial cell proliferation was the same as that of FGF-2. Affinities of the mutants to heparin and to cells that express FGF receptor-1 (FGFR-1) were identical to those of the wild-type protein. The role of the loop structure in FGF-1 and FGF-2 was elucidated by using soluble FGF receptor systems, which display distinct ligand binding specificities. Thus, FGF-2LA bound, with the same affinity as FGF-1 and FGF-2, to FGFR-1 and FGFR-2, whereas only FGF-1 and the FGF-1 loop-containing mutant, FGF-2LA, bound to the keratinocyte growth factor receptor. A change in receptor binding specificity was not observed with the FGF-2LI engineered mutant. That the binding specificity of FGF-2 was dramatically altered by transfer of a loop structure from FGF-1 to resemble the binding profile of the donor protein provides strong evidence that this motif is a receptor binding specificity determinant of fibroblast growth factors.

3T3 Cells↗

PubMed1995

1H, 15N, 13C and 13CO assignments and secondary structure determination of basic fibroblast growth factor using 3D heteronuclear NMR spectroscopy.

The assignments of the 1H, 15N, 13CO and 13C resonances of recombinant human basic fibroblast growth factor (FGF-2), a protein comprising of 154 residues and with a molecular mass of 17.2 kDa, is presented based on a series of three-dimensional triple-resonance heteronuclear NMR experiments. These studies employ uniformly labeled 15N- and 15N-/13C-labeled FGF-2 with an isotope incorporation > 95% for the protein expressed in E. coli. The sequence-specific backbone assignments were based primarily on the interresidue correlation of C alpha, C beta and H alpha to the backbone amide 1H and 15N of the next residue in the CBCA(CO)NH and HBHA(CO)NH experiments and the intraresidue correlation of C alpha, C beta and H alpha to the backbone amide 1H and 15N in the CBCANH and HNHA experiments. In addition, C alpha and C beta chemical shift assignments were used to determine amino acid types. Sequential assignments were verified from carbonyl correlations observed in the HNCO and HCACO experiments and C alpha correlations from the HNCA experiment. Aliphatic side-chain spin systems were assigned primarily from H(CCO)NH and C(CO)NH experiments that correlate all the aliphatic 1H and 13C resonances of a given residue with the amide resonance of the next residue. Additional side-chain assignments were made from HCCH-COSY and HCCH-TOCSY experiments. The secondary structure of FGF-2 is based on NOE data involving the NH, H alpha and H beta protons as well as 3JHNH alpha coupling constants, amide exchange and 13C alpha and 13C beta secondary chemical shifts. It is shown that FGF-2 consists of 11 well-defined antiparallel beta-sheets (residues 30-34, 39-44, 48-53, 62-67, 71-76, 81-85, 91-94, 103-108, 113-118, 123-125 and 148-152) and a helix-like structure (residues 131-136), which are connected primarily by tight turns. This structure differs from the refined X-ray crystal structures of FGF-2, where residues 131-136 were defined as beta-strand XI. The discovery of the helix-like region in the primary heparin-binding site (residues 128-138) instead of the beta-strand conformation described in the X-ray structures may have important implications in understanding the nature of heparin-FGF-2 interactions. In addition, two distinct conformations exist in solution for the N-terminal residues 9-28. This is consistent with the X-ray structures of FGF-2, where the first 17-19 residues were ill defined.

Escherichia coli↗

PubMed1995

Chromosomal assignment of the heparin-binding cytokine genes MDK and PTN in mouse and man.

MDK and PTN are two members of a family of heparin-binding cytokines thought to be involved in a number of developmental processes. The locations for these genes were determined in man and mouse using somatic cell hybrid analysis and interspecific backcross analysis. Human MDK was mapped to 11p13-->p11. MDK in the mouse (Mdk) was mapped to a syntenic region of mouse Chromosome 2. A pseudogene of Mdk was mapped to mouse Chromosome 11. The closely related human gene PTN was mapped to a separate location on human chromosome region 7q22-->qter.

Animals↗

PubMed1995

Different molecular forms of basic fibroblast growth factor (bFGF) accelerate duodenal ulcer healing in rats.

UNLABELLED: Basic fibroblast growth factor is an angiogenic polypeptide that exhibits potent antiulcer activity without decreasing gastric acid or pepsin secretion. In this study, we investigated the effect of three acid-stable derivatives of human recombinant bFGF (hrbFGF) on the healing of chronic duodenal ulcer in rats. In Sprague-Dawley female rats, duodenal ulcers were induced by cysteamine-HCl. After laparotomy, rats were randomized to create six groups with homogeneously severe ulcers (perforated or penetrated into the liver or pancreas) and treated by gavage twice a day for 3 weeks with a) vehicle, b) cimetidine (10 mg/100 g), c) Ser78,96-hrbFGF (bioequivalent to rbFGF-CS23), d) CMC-hrbFGF, a carboxymethyl cysteine derivative of hrbFGF or e) PEG-hrbFGF, a polyethylene glycol derivative of hrbFGF. The peptides were administered at 100 ng/100 g. Autopsy was performed on the 21st day, and the ulcer size was measured. The ulcer sizes (mm2) were reduced from 10.3 +/- 1.8 in controls to 4.8 +/- 1.4* after cimetidine treatment and to 5.0 +/- 2.4, 4.2 +/- 1.1* and 0.5 +/- 0.2**, respectively, after administration of aforementioned hrbFGF derivatives (*P < .05; **P < .01 vs. vehicle group), which also significantly enhanced angiogenesis in the ulcer bed. CONCLUSIONS: 1) Oral administration of novel derivatives of hrbFGF accelerated the healing of cysteamine-induced chronic duodenal ulcer. 2) The PEG-hrbFGF derivative was more active than the other hrbFGF analogs. 3) The naturally occurring bFGF provides a good prototype to design new locally acting antiulcer drugs.

Animals↗

PubMed1994

Biological activity and phosphorylation sites of the bacterially expressed cytosolic domain of the KDR VEGF-receptor.

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor which binds to two structurally similar receptor tyrosine kinases, KDR and FLT1. Towards the goal of clarifying the signal transduction pathways by which VEGF activates endothelial cells, we expressed in bacteria an enzymatically active form of the cytosolic domain of the KDR receptor. The expressed protein undergoes autophosphorylation in both bacterial cells and in its purified form. Using peptide mapping and sequencing of peptides, we identified four tyrosine residues that are phosphorylated corresponding to residues 951, 996, 1054, and 1059 of the KDR protein. The location of the phosphorylated residues in the bacterially expressed protein, and/or the consensus sequences around these sites, suggest they may be identical to the phosphorylated sites of KDR in mammalian cells.

Amino Acid Sequence↗

PubMed1994

Diminished heparin binding of a basic fibroblast growth factor mutant is associated with reduced receptor binding, mitogenesis, plasminogen activator induction, and in vitro angiogenesis.

Using modeling of heparin-fibroblast growth factor interactions, we replaced four basic residues of basic fibroblast growth factor (FGF-2) with neutral glutamine residues by site-specific mutagenesis to give the mutants K128Q, K138Q, K128Q-K138Q, R129Q, K134Q, and R129Q-K134Q. The FGF mutants were characterized for their receptor and heparin binding affinities, mitogenic and cell proliferation activities, and their ability to induce plasminogen activator (PA) production and in vitro angiogenesis by cultured endothelial cells. Heparin binding properties and biological activities of the three mutants involving R129 and K134 remained essentially unchanged; however, significant changes for three mutants involving K128 and K138 were found. The KD values for heparin binding for K128Q and K138Q mutants were increased about 10-fold, and that for the K128Q-K138Q double mutant was increased by about 100-fold. The mutant K128Q-K138Q required a 10-fold higher concentration of heparin to promote binding to heparan sulfate proteoglycan (HSPG)-deficient CHO cells transfected with fibroblast growth factor receptor-1 (FGFR1) or to induce DNA synthesis in HSPG-deficient myeloid cells transfected with FGFR1. Binding affinities of the mutants to cell surface receptors on BHK-21 cells, however, were similar to that of wild-type FGF-2. In endothelial cell proliferation assays the activities of K128Q and K128Q-K138Q were about 10-fold lower than that of the wild-type protein, whereas the K138Q mutant exhibited wild-type activity. In addition, the K128Q-K138Q mutant displayed a markedly lowered capacity to induce PA activity in cultured endothelial cells and to form capillary-like structures in an in vitro angiogenesis model.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Refolding and characterization of human recombinant heparin-binding neurite-promoting factor.

Heparin-binding neurite-promoting factor (HBNF) is a highly basic, cysteine-rich 136-residue protein, and a member of a new class of heparin-binding proteins. It exhibits a neurite-outgrowth promoting activity and its expression is both temporally and spacially regulated during fetal and postnatal development. A high interspecies sequence conservation suggests important, presently unknown, biological functions. HBNF is structurally and most likely functionally related to the product of a developmentally regulated gene, MK (midkine). To elucidate biological roles of these proteins, recombinant forms of the proteins were produced. Expression of human recombinant HBNF and MK in Escherichia coli lead to the formation of insoluble aggregated protein that accounted for about 25% of the total cellular protein. Homogeneous, monomeric forms of each protein were recovered from inclusion bodies by reduction with dithiothreitol and solubilization in 8 M urea. Refolding of the reduced and denatured protein occurred upon dialysis at pH 7.4. Human recombinant (hr) HBNF and hrMK prepared in this manner were further purified by heparin affinity chromatography. Chromatographic evidence demonstrates that refolding and concomitant disulfide bond formation in hrHBNF proceeds in high yield with minimal formation of stable nonnative disulfides. Studies on the redox status of the 10 cysteine residues of bovine brain HBNF and the refolded recombinant protein indicate that all cysteines are engaged in disulfide bond formation. The disulfide arrangements for the recombinant protein were found to be identical to those in the native protein isolated from bovine brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

PubMed1994

VEGF receptor subtypes KDR and FLT1 show different sensitivities to heparin and placenta growth factor.

Vascular endothelial growth factor (VEGF) is an angiogenic growth factor which binds to two structurally related tyrosine kinase receptors denoted KDR and FLT1. To compare the interaction of VEGF with each receptor, cell lines which express individual receptor subtypes were identified using Northern blot hybridization. Bovine aortic endothelial (ABAE) cells and WM35 melanoma cells were found to express KDR, while FLT1 was primarily expressed on SK-MEL-37. Both receptor subtypes were detected on another melanoma cell line (WM9). Heparin augmented VEGF binding to KDR-expressing cells (ABAE and WM35), but inhibited VEGF binding to FLT1-expressing cells (SK-MEL-37 and WM9). The concentration of heparin required for half maximal stimulation of VEGF binding to KDR-expressing cells (500 ng/ml) was 25 times greater than that required for half maximal inhibition of binding to FLT1-expressing cells (20 ng/ml). In WM9 cells, the effect of heparin was bimodal; low concentration inhibited, while higher concentrations stimulated binding of 125I-VEGF. Placenta growth factor (PIGF-1) is a recently described growth factor structurally similar to VEGF. PIGF-1 had a negligible or no effect on 125I-VEGF binding to KDR-expressing cells (ABAE, WM35), but did complete for binding to FLT1-expressing cells (SK-MEL-37 and WM9). Addition of heparin had no effect on its ability to compete for binding with 125I-VEGF. The data indicate differential regulation of the two VEGF receptors by heparin and extended specificity of FLT1 receptor, but not KDR, for binding PIGF-1 growth factor.

Animals↗

PubMed1993

Genomic organization of the human HBNF gene and characterization of an HBNF variant protein as a splice mutant.

The organization of the human heparin-binding neurite outgrowth promoting factor (HBNF) gene is presented. Based on Southern analysis and the isolation of genomic DNA clones from a lambda phage library, the minimum size of the gene is 42 kb. Sequences comprising the HBNF mRNA are contained in five exons which account for the 1650 nt mRNA size observed by northern analysis. From the structure of the gene it is predicted that a variant human HBNF cDNA with a three basepair deletion is a result of alternative splicing at the acceptor site of exon 5. Evidence is presented that indicates the existence of a variant HBNF protein, des-Ala119-HBNF, in bovine brain which has a corresponding amino acid deletion. This alternate form comprises approximately 20% of the total HBNF protein present in bovine brain.

Alternative Splicing↗

PubMed1993

Comparison of the disulfide bond arrangements of human recombinant and bovine brain heparin binding neurite-promoting factors.

Heparin binding neurite-promoting factor (HBNF) is a highly basic 136 amino acid protein containing 10 cysteine residues. We have determined the redox status and the disulfide arrangement of the cysteine residues in HBNF from bovine brain and refolded human recombinant protein produced in E. coli. Our data indicate that all 10 cysteines are involved in disulfide bond formation. The disulfide linkages of human recombinant and bovine brain HBNF, as determined after proteolytic digestions of the non-reduced proteins by peptide mapping and sequence analysis are: Cys15-Cys44, Cys23-Cys53, Cys30-Cys57, Cys67-Cys99 and Cys77-Cys109. Thus, recombinant HBNF has the same disulfide arrangement as the native brain-derived protein.

Amino Acid Sequence↗

PubMed1993

Structure of the gene coding for the human retinoic acid-inducible factor, MK.

The retinoic acid-inducible MK gene shows a distinct developmental pattern of expression, which implies that it has potential growth regulation and differentiation functions, particularly in the brain. We report here the cloning of the human MK gene from a phage library constructed from placental tissue. The structure of this gene has been determined using Southern hybridization and DNA sequence analysis. An isolated fragment was cloned and found to contain sequences identical to those of a previously isolated human MK cDNA clone, MKHC4. The gene contains three introns within the MK coding region as well as additional sequence, which indicates the presence of an intron prior to the putative protein start site. As judged by sequence analysis of cDNA clones, primer extension studies, and Northern analysis, the most abundant human MK message corresponds to the major mRNA of the previously described mouse gene. Primer extension studies and cDNA sequence data suggest that minor messages may be transcribed from the human gene, but no evidence of additional messages has been found by Northern analysis. This is in contrast to the mouse MK gene, from which three mRNAs are transcribed. Nevertheless, the similarity in the overall genomic structure of the human and mouse genes is striking.

Amino Acid Sequence↗

PubMed1993

A glycosylation-deficient endothelial cell mutant with modified responses to transforming growth factor-beta and other growth inhibitory cytokines: evidence for multiple growth inhibitory signal transduction pathways.

An endothelial cell line (M40) resistant to growth inhibition by transforming growth factor-beta type 1 (TGF beta 1) was isolated by chemical mutagenesis and growth in the presence of TGF beta 1. Like normal endothelial cells, this mutant is characterized by high expression of type II TGF beta receptor and low expression of type I TGF beta receptor. However, the mutant cells display a type II TGF beta receptor of reduced molecular weight as a result of a general defect in N-glycosylation of proteins. The alteration does not impair TGF beta 1 binding to cell surface receptors or the ability of TGF beta 1 to induce fibronectin or plasminogen activator inhibitor-type I production. M40 cells were also resistant to growth inhibition by tumor necrosis factor alpha (TNF alpha) and interleukin-1 alpha (IL-1 alpha) but were inhibited by interferon-gamma (IFN gamma) and heparin. These results imply that TGF beta 1, TNF alpha, and IL-1 alpha act through signal transducing pathways that are separate from pathways for IFN gamma and heparin. Basic fibroblast growth factor was still mitogenic for M40, further suggesting that TGF beta 1, TNF alpha, and IL-1 alpha act by direct inhibition of cell growth rather than by interfering with growth stimulatory pathways.

Animals↗

PubMed1992

Expression of the HBNF (heparin-binding neurite-promoting factor) gene in the brain of fetal, neonatal and adult rat: an in situ hybridization study.

HBNF (heparin-binding neurite-promoting factor) and MK (midkine) are members of a newly recognized family of proteins, the expression of which is developmentally regulated. These proteins are expressed highest during fetal development in many tissues but they seem to be rather restricted to the brain in adult animals. Gene expression for these proteins is inducible by retinoic acid in embryonal carcinoma cell lines. They induce neurite outgrowth in cultured neurons, and they are characterized by high sequence conservation between species. While the function(s) of these proteins are unknown, available evidence suggests possible roles in the development and the maintenance of neural tissues. This in situ hybridization study investigates the temporal and spatial expression pattern of the HBNF gene in the brain of developing rats. The HBNF gene is highly expressed in the neuroepithelium and the ependyma from fetal day 15 on. Although most ependymal structures express the gene strongly, a few restricted areas of the ependyma do not express HBNF (ventral part of the fourth ventricle, subcommissural organ). In the brain parenchyma, HBNF is expressed in the thalamo-hippocampal area from fetal day 15 and in the cerebral cortex from fetal day 16, with high expression occurring in the superficial layers of the cortex. The nature of the cells expressing the gene, while difficult to ascertain, is probably glial for the most part. However, certain neurons (in limited areas of the brain parenchyma) and most pial cells (in the meninges), also express the gene. HBNF gene expression decreases sharply a few days after birth. HBNF mRNA is also detectable at fetal days 15 and 16 in the face fetal mesenchyma. In the adult rat brain, the expression of the HBNF gene appears to be restricted to neurons of the hippocampus and of the olfactory bulb and to the superficial layers of the cortex. The structurally related MK gene, though not extensively studied here, shows an entirely different temporal and spatial expression pattern. MK gene is weakly expressed during ontogeny in most brain areas, and in the adult animal, MK mRNA is present only in the choroid plexus. The intense and widely distributed expression of the HBNF gene in several cell populations in the fetus, the progressive spatial and quantitative restriction of HBNF gene expression with brain differentiation, as well as the properties of the protein suggest important and diverse functions for HBNF in cellular interactions and cell differentiation in the developing brain, that must act temporally and spatially by ways distinct from its MK companion molecule.

Amino Acid Sequence↗

PubMed1992

Anti-viral activity of human recombinant heparin-binding proteins HBNF and MK.

Herpes simplex viruses bind to cell surface heparan sulfate proteoglycans, as a first step of viral infection. We report here that two recombinant heparin-binding proteins HBNF and MK inhibit infectivity of human herpes simplex viruses types 1 and 2 and human cytomegalovirus. Carboxymethylated HBNF and MK, which retain affinity for heparin-Sepharose, do not exhibit anti-viral activities. Arguments are presented that anti-viral effects of HBNF and MK are due to the competition for the specific binding to the cell surface heparan sulfate proteoglycans.

Alkylation↗