Activin A binds to perlecan through its pro-region that has heparin/heparan sulfate binding activity.
Activin A, a member of the transforming growth factor-β 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 perlecan-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.
Li
Shaoliang
S
Laboratory of Extracellular Matrix Biochemistry, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Shimono
Chisei
C
Norioka
Naoko
N
Nakano
Itsuko
I
Okubo
Tetsuo
T
Yagi
Yoshiko
Y
Hayashi
Maria
M
Sato
Yuya
Y
Fujisaki
Hitomi
H
Hattori
Shunji
S
Sugiura
Nobuo
N
Kimata
Koji
K
Sekiguchi
Kiyotoshi
K
D028341:Activins / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D007797:Laminin / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D028341:Activins; D016326:Extracellular Matrix Proteins; D019812:Heparan Sulfate Proteoglycans; D006493:Heparin; D006497:Heparan Sulfate; D007797:Laminin; D008156:Luciferases; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; C422405:activin A; C432915:nephronectin; C029967:nidogen; C071927:perlecan