The Biological Role of Klotho Protein in the Development of Cardiovascular Diseases

Figure 1

The scheme of membrane-bound and soluble (shed and secreted) forms of αKlotho. (a) Membrane-bound αKlotho is created by 3 domains: cytoplasmic (CYT), transmembrane (TM), and ectodomain. The ectodomain has two internal repeats, KL1 and KL2. Membrane-bound αKlotho is subjected to shedding of ectodomain by ADAM 10 or 17 protease in two ways to release three shed αKlotho. The alternative transcriptional termination of kl gene expression leads to generation of secreted αKlotho. (b) Membrane-bound αKlotho forms a complex with FGFR to create a high-affinity binding site for FGF23. ADAM, a disintegrin and metalloproteinase domain-containing protein; FGFR, fibroblast growth factor receptor; FGF23, fibroblast growth factor 23.