Figure 2.

Klotho-mediated retention of TRPV5 on the cell surface. The number of TRPV5 channels on the cell membrane through which calcium influx is achieved is dependent on the final balance between two counterbalancing mechanisms: protein insertion via the Golgi apparatus and protein removal via endocytosis in endosomes. LacNac (N-acetyllactosamine) is a ligand for galactin-1. Sialic acids prevent binding of LacNac to galectin-1. Removal of the terminal sialic acids from N-glycan of TRPV5 channels by secreted Klotho permits binding of LacNac to galecting-1 preventing channel endocytosis. That will eventually result in accumulation of TRPV5 on the cell surface and increased calcium flow into the cell. TRPV, transient receptor potential vaniloid.