TY - JOUR
T1 - TGF-2 uses the concave surface of its extended finger region to bind betaglycan’s ZP domain via three residues specific to TGF- and inhibin-
AU - Henen, Morkos A.
AU - Mahlawat, Pardeep
AU - Zwieb, Christian
AU - Kodali, Ravindra B.
AU - Hinck, Cynthia S.
AU - Hanna, Ramsey D.
AU - Krzysiak, Troy C.
AU - Ilangovan, Udayar
AU - Cano, Kristin E.
AU - Hinck, Garrett
AU - Vonberg, Machell
AU - McCabe, Megan
AU - Hinck, Andrew P.
N1 - Funding Information:
Acknowledgments—David Brinkman is thanked for the initial efforts to generate and characterize several TGF-β2 variants; Erich Helle-mann for measuring the mass of the TGF-β2 variants; Mike Delk for maintaining the NMR instruments, and Profs. Craig Harrison and Daniel Bernard for providing valuable comments on the manuscript. Molecular graphics and analyses were performed with UCSF Chimera. Chimera is developed by the Resource for Biocomputing, Visualization, and Informatics at the University of California, San Francisco (supported by National Institutes of Health NIGMS Grant P41-GM103311).
Funding Information:
This work was supported by National Institutes of Health Grants GM58670 and CA172886 and the University of Pittsburgh Vascular Medicine Insti-tute. The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2019 Henen et al. Published under exclusive license by The American Society for Biochemistry and Molecular Biology, Inc.
PY - 2019/3/1
Y1 - 2019/3/1
N2 - Betaglycan (BG) is a membrane-bound co-receptor of the TGF- family that selectively binds transforming growth factor- (TGF-) isoforms and inhibin A (InhA) to enable temporal-spatial patterns of signaling essential for their functions in vivo. Here, using NMR titrations of methyl-labeled TGF-2 with BG’s C-terminal binding domain, BGZP-C, and surface plasmon resonance binding measurements with TGF-2 variants, we found that the BGZP-C– binding site on TGF-2 is located on the inner surface of its extended finger region. Included in this binding site are Ile-92, Lys-97, and Glu-99, which are entirely or mostly specific to the TGF- isoforms and the InhA -subunit, but they are unconserved in other TGF- family growth factors (GFs). In accord with the proposed specificity-determining role of these residues, BG bound bone morphogenetic protein 2 (BMP-2) weakly or not at all, and TGF-2 variants with the corresponding residues from BMP-2 bound BGZP-C more weakly than corresponding alanine variants. The BGZP-C– binding site on InhA previously was reported to be located on the outside of the extended finger region, yet at the same time to include Ser-112 and Lys-119, homologous to TGF-2 Ile-92 and Lys-97, on the inside of the fingers. Therefore, it is likely that both TGF-2 and InhA bind BGZP-C through a site on the inside of their extended finger regions. Overall, these results identify the BGZP-C– binding site on TGF-2 and shed light on the specificity of BG for select TGF-–type GFs and the mechanisms by which BG influences their signaling.
AB - Betaglycan (BG) is a membrane-bound co-receptor of the TGF- family that selectively binds transforming growth factor- (TGF-) isoforms and inhibin A (InhA) to enable temporal-spatial patterns of signaling essential for their functions in vivo. Here, using NMR titrations of methyl-labeled TGF-2 with BG’s C-terminal binding domain, BGZP-C, and surface plasmon resonance binding measurements with TGF-2 variants, we found that the BGZP-C– binding site on TGF-2 is located on the inner surface of its extended finger region. Included in this binding site are Ile-92, Lys-97, and Glu-99, which are entirely or mostly specific to the TGF- isoforms and the InhA -subunit, but they are unconserved in other TGF- family growth factors (GFs). In accord with the proposed specificity-determining role of these residues, BG bound bone morphogenetic protein 2 (BMP-2) weakly or not at all, and TGF-2 variants with the corresponding residues from BMP-2 bound BGZP-C more weakly than corresponding alanine variants. The BGZP-C– binding site on InhA previously was reported to be located on the outside of the extended finger region, yet at the same time to include Ser-112 and Lys-119, homologous to TGF-2 Ile-92 and Lys-97, on the inside of the fingers. Therefore, it is likely that both TGF-2 and InhA bind BGZP-C through a site on the inside of their extended finger regions. Overall, these results identify the BGZP-C– binding site on TGF-2 and shed light on the specificity of BG for select TGF-–type GFs and the mechanisms by which BG influences their signaling.
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U2 - 10.1074/jbc.RA118.005210
DO - 10.1074/jbc.RA118.005210
M3 - Article
C2 - 30598510
AN - SCOPUS:85063478609
SN - 0021-9258
VL - 294
SP - 3065
EP - 3080
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 9
ER -