title: Recombinant hemangiopoietin promotes cell adhesion and binds heparin             in its multimeric form.
abstract: Hemangiopoietin (HAPO) is a novel growth factor stimulating the proliferation             of hematopoietic and endothelial progenitor cells in vitro and in vivo. The native             protein is a 294‑amino acid multimodular protein. The N‑terminus constitutes of             two somatomedin B (SMB) homology domains that contain 14 cysteines. The central             region is a putative heparin‑binding domain (pHBD) and the C‑terminus contains             mucin‑like repeats. In the present study, we demonstrated that prokaryotic recombinant             human HAPO (rhHAPO) self‑associates into a multimeric form with a mass weight             of ~129 kDa, suggesting a homologous tetramer. rhHAPO in its multimeric form was             found to be more stable and more potent in promoting HESS‑5 cell adhesion. Multimeric             rhHAPO had a higher affinity to heparin compared with its dimeric form, although             there was no significant conformational change. C‑terminal repeats-truncated rhHAPO             (rhHAPOΔmucin) was also found to be assembled into a multimer, while deletion             of pHBD (rhHAPOΔmucin‑pHBD) caused the protein to remain in a dimeric form, demonstrating             that SMB domains participate in self‑aggregation of the molecule and that the             pHBD region promotes the tetramerization.
authors: Department of Basic Medicine, Zhejiang Medical College, Hangzhou 310053, PR China.
authors: Li-Fang
authors: LF
authors: Wang
authors: Zhi-Bo
authors: ZB
authors: Han
authors: Mei
authors: M
authors: Li
authors: Ping
authors: P
authors: Yang
authors: Bin
authors: B
authors: Xv
authors: Ji-Ping
authors: JP
authors: Zhang
authors: Zhong-Chao
authors: ZC
authors: Han
mesh_terms: D002448:Cell Adhesion / Q000187:drug effects; D002942:Circular Dichroism; D019281:Dimerization; D006493:Heparin / Q000378:metabolism*; D006801:Humans; D011485:Protein Binding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011509:Proteoglycans / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D000099158:Proteoglycan 4
chemical_list: D006493:Heparin; D011509:Proteoglycans; D011994:Recombinant Proteins; C419197:PRG4 protein, human; D000099158:Proteoglycan 4