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Soluble klotho binds monosialoganglioside to regulate membrane microdomains and growth factor signaling
Journal article   Open access   Peer reviewed

Soluble klotho binds monosialoganglioside to regulate membrane microdomains and growth factor signaling

George Dalton, Sung-Wan An, Saif I Al-Juboori, Nicole Nischan, Joonho Yoon, Evgenia Dobrinskikh, Donald W Hilgemann, Jian Xie, Kate Luby-Phelps, Jennifer J Kohler, …
Proceedings of the National Academy of Sciences - PNAS, Vol.114(4), pp.752-757
01/24/2017
DOI: 10.1073/pnas.1620301114
PMCID: PMC5278494
PMID: 28069944
url
https://doi.org/10.1073/pnas.1620301114View
Published (Version of record) Open Access

Abstract

Soluble klotho, the shed ectodomain of the antiaging membrane protein α-klotho, is a pleiotropic endocrine/paracrine factor with no known receptors and poorly understood mechanism of action. Soluble klotho down-regulates growth factor-driven PI3K signaling, contributing to extension of lifespan, cardioprotection, and tumor inhibition. Here we show that soluble klotho binds membrane lipid rafts. Klotho binding to rafts alters lipid organization, decreases membrane’s propensity to form large ordered domains for endocytosis, and down-regulates raft-dependent PI3K/Akt signaling. We identify α2-3-sialyllactose present in the glycan of monosialogangliosides as targets of soluble klotho. α2-3-Sialyllactose is a common motif of glycans. To explain why klotho preferentially targets lipid rafts we show that clustering of gangliosides in lipid rafts is important. In vivo, raft-dependent PI3K signaling is up-regulated in klotho-deficient mouse hearts vs. wild-type hearts. Our results identify ganglioside-enriched lipid rafts to be receptors that mediate soluble klotho regulation of PI3K signaling. Targeting sialic acids may be a general mechanism for pleiotropic actions of soluble klotho.
Cell Line Membrane Microdomains - metabolism Humans Glucuronidase - metabolism Phosphatidylinositol 3-Kinases - metabolism Biophysical Phenomena - physiology Intercellular Signaling Peptides and Proteins - metabolism Animals Gangliosides - metabolism HEK293 Cells Cell Line, Tumor Signal Transduction - physiology Mice HeLa Cells

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