TY - JOUR
T1 - Modeled structural basis for the recognition of a2-3-sialyllactose by soluble Klotho
AU - Wright, Jon D.
AU - An, Sung Wan
AU - Xie, Jian
AU - Yoon, Joonho
AU - Nischan, Nicole
AU - Kohler, Jennifer J.
AU - Oliver, Noelynn
AU - Lim, Carmay
AU - Huang, Chou Long
N1 - Funding Information:
This work was supported, in part, by the Academia Sinica and Ministry of Science and Technology (MOST) of Taiwan (Grant 98-2113-M-001-011), the U.S. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases (Grants DK109887 and DK100605), the Welch Foundation (Grant I-1686), and by a sponsored research agreement between University of Texax Southwestern and Boehringer Ingelheim Pharmaceuticals Inc. (BIPI). BIPI provided purified recombinant KL1 domain protein. N.N. is supported by a postdoctoral fellowship from the German Academic Exchange Service (DAAD). The authors thank M. Diamond and J. Vaquer-Alicea (both from the University of Texas Southwestern Medical Center, Dallas, TX, USA) for provision of the Octet.
Publisher Copyright:
© FASEB
PY - 2017/8
Y1 - 2017/8
N2 - Soluble Klotho (sKlotho) is the shed ectodomain of antiaging membrane Klotho that contains 2 extracellular domains KL1 and KL2, each of which shares sequence homology to glycosyl hydrolases. sKlotho elicits pleiotropic cellular responses with a poorly understood mechanism of action. Notably, in injury settings, sKlotho confers cardiac and renal protection by down-regulating calcium-permeable transient receptor potential canonical type isoform 6 (TRPC6) channels in cardiomyocytes and glomerular podocytes. Inhibition of PI3K-dependent exocytosis of TRPC6 is thought to be the underlying mechanism, and recent studies showed that sKlotho interacts with a2-3-sialyllactose-containing gangliosides enriched in lipid rafts to inhibit raft-dependent PI3K signaling. However, the structural basis for binding and recognition of a2-3-sialyllactose by sKlotho is unknown. Using homology modeling followed by docking, we identified key protein residues in the KL1 domain that are likely involved in binding sialyllactose. Functional experiments based on the ability of Klotho to down-regulate TRPC6 channel activity confirm the importance of these residues. Furthermore, KL1 domain binds a2-3-sialyllactose, down-regulates TRPC6 channels, and exerts protection against stress-induced cardiac hypertrophy in mice. Our results support the notion that sialogangliosides and lipid rafts are membrane receptors for sKlotho and that the KL1 domain is sufficient for the tested biologic activities. These findings can help guide the design of a simpler Klotho mimetic.—Wright, J. D., An, S.-W., Xie, J., Yoon, J., Nischan, N., Kohler, J. J., Oliver, N., Lim, C., Huang, C.-L. Modeled structural basis for the recognition of a2-3-sialyllactose by soluble Klotho.
AB - Soluble Klotho (sKlotho) is the shed ectodomain of antiaging membrane Klotho that contains 2 extracellular domains KL1 and KL2, each of which shares sequence homology to glycosyl hydrolases. sKlotho elicits pleiotropic cellular responses with a poorly understood mechanism of action. Notably, in injury settings, sKlotho confers cardiac and renal protection by down-regulating calcium-permeable transient receptor potential canonical type isoform 6 (TRPC6) channels in cardiomyocytes and glomerular podocytes. Inhibition of PI3K-dependent exocytosis of TRPC6 is thought to be the underlying mechanism, and recent studies showed that sKlotho interacts with a2-3-sialyllactose-containing gangliosides enriched in lipid rafts to inhibit raft-dependent PI3K signaling. However, the structural basis for binding and recognition of a2-3-sialyllactose by sKlotho is unknown. Using homology modeling followed by docking, we identified key protein residues in the KL1 domain that are likely involved in binding sialyllactose. Functional experiments based on the ability of Klotho to down-regulate TRPC6 channel activity confirm the importance of these residues. Furthermore, KL1 domain binds a2-3-sialyllactose, down-regulates TRPC6 channels, and exerts protection against stress-induced cardiac hypertrophy in mice. Our results support the notion that sialogangliosides and lipid rafts are membrane receptors for sKlotho and that the KL1 domain is sufficient for the tested biologic activities. These findings can help guide the design of a simpler Klotho mimetic.—Wright, J. D., An, S.-W., Xie, J., Yoon, J., Nischan, N., Kohler, J. J., Oliver, N., Lim, C., Huang, C.-L. Modeled structural basis for the recognition of a2-3-sialyllactose by soluble Klotho.
KW - KL1 domain
KW - PI3K
KW - TRPC6
UR - http://www.scopus.com/inward/record.url?scp=85026805161&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85026805161&partnerID=8YFLogxK
U2 - 10.1096/fj.201700043R
DO - 10.1096/fj.201700043R
M3 - Article
C2 - 28442546
AN - SCOPUS:85026805161
SN - 0892-6638
VL - 31
SP - 3574
EP - 3586
JO - FASEB Journal
JF - FASEB Journal
IS - 8
ER -