NCBI and Uniprot Product Information
Uniprot Description
Klotho: May have weak glycosidase activity towards glucuronylated steroids. However, it lacks essential active site Glu residues at positions 239 and 872, suggesting it may be inactive as a glycosidase in vivo. May be involved in the regulation of calcium and phosphorus homeostasis by inhibiting the synthesis of active vitamin D. Essential factor for the specific interaction between FGF23 and FGFR1. Defects in KL are a cause of hyperphosphatemic familial tumoral calcinosis (HFTC). A severe metabolic disorder that manifests with hyperphosphatemia and massive calcium deposits in the skin and subcutaneous tissues. Some patients manifest recurrent, transient, painful swellings of the long bones associated with the radiographic findings of periosteal reaction and cortical hyperostosis and absence of skin involvement. Belongs to the glycosyl hydrolase 1 family. Klotho subfamily. 2 isoforms of the human protein are produced by alternative splicing.
Protein type: EC 3.2.1.31; Hydrolase; Membrane protein, integral
Chromosomal Location of Human Ortholog: 13q12
Cellular Component: extracellular region; integral to plasma membrane; plasma membrane
Molecular Function: 1-phosphatidylinositol-3-kinase activity; beta-glucosidase activity; fibroblast growth factor binding; fibroblast growth factor receptor binding; phosphatidylinositol-4,5-bisphosphate 3-kinase activity; Ras guanyl-nucleotide exchange factor activity
Biological Process: aging; fibroblast growth factor receptor signaling pathway; MAPKKK cascade; phosphoinositide-mediated signaling; positive regulation of bone mineralization; regulation of phosphoinositide 3-kinase cascade
Disease: Tumoral Calcinosis, Hyperphosphatemic, Familial