Activin A Binds to Perlecan through Its Pro-region That Has Heparin/Heparan Sulfate Binding Activity
Activin A Binds to Perlecan through Its Pro-region That Has Heparin/Heparan Sulfate Binding Activity
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DOI：
10.1074/jbc.m110.177865
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发表时间：
2010-11-19
影响因子：
4.8
通讯作者：
Sekiguchi, Kiyotoshi
中科院分区：
文献类型：
--
作者：
Li, Shaoliang;Shimono, Chisei;Sekiguchi, Kiyotoshi
Activin A, a member of the transforming growth factor-beta family, plays important roles in hormonal homeostasis and embryogenesis. In this study, we produced recombinant human activin A and examined its abilities to bind to extracellular matrix proteins. Recombinant activin A expressed in 293-F cells was purified as complexes of mature dimeric activin A with its pro-region. Among a panel of extracellular matrix proteins tested, recombinant activin A bound to perlecan and agrin, but not to laminins, nidogens, collagens I and IV, fibronectin, and nephronectin. The binding of recombinant activin A to perlecan was inhibited by heparin and high concentrations of NaCl and abolished by heparitinase treatment of perlecan, suggesting that activin A binds to the heparan sulfate chains of perlecan. In support of this possibility, recombinant activin A was capable of directly binding to heparin and heparan sulfate chains. Site-directed mutagenesis of recombinant activin A revealed that clusters of basic amino acid residues, Lys(259)-Lys(263) and Lys(270)-Lys(272), in the pro-region were required for binding to perlecan. Interestingly, deletion of the peptide segment Lys(259)-Gly(277) containing both basic amino acid clusters from the pro-region did not impair the activity of activin A to stimulate Smad-dependent gene expressions, although it completely ablated the perle-can-binding activity. The binding of activin A to basement membrane heparan sulfate proteoglycans through the basic residues in the pro-region was further confirmed by in situ activin A overlay assays using frozen tissue sections. Taken together, the present results indicate that activin A binds to heparan sulfate proteoglycans through its pro-region and thereby regulates its localization within tissues.
