Referenced in: none

Automatically associated channels: Kir1.1 , TRP , TRPV , TRPV5

Title: Regulation of ion channels by secreted klotho.

Authors: Chou-Long Huang

Journal, date & volume: Adv. Exp. Med. Biol., 2012 , 728, 100-6

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22396165

Abstract
Klotho is an anti-aging protein predominantly expressed in the kidney, parathyroid glands and choroid plexus of the brain. Klotho exists in two forms, a membrane form and a soluble secreted form. Recent studies show that the secreted Klotho possess sialidase activity and regulates several ion channels via the activity. Removal of terminal sialic acids from N-glycan chains of the epithelial Ca(2+) channel TRPV5 and the renal K(+) channel ROMK by secreted Klotho exposes the underlying disaccharide galactose-N-acetylglucosamine, a ligand for galectin-1. Binding to galectin-1 at the extracellular surface prevents internalization and leads to accumulation of the channels on the plasma membrane. Future studies will investigate whether secreted Klotho regulates cell-surface expression of other membrane glycoproteins via the same mechanism.