Cubilin

• OMIM: 602997
• UniProt: O60494

Cubilin (gene name: CUBN ), and intrinsic factor - cobalamin receptor, is a protein in the cell membrane of multiple tissues and acts as a receptor. It is one of two major proteins that are involved in endocytosis. Cubilin is present in all mouths jaw and thus also in humans. Mutations in the gene can CUBN Cubilinmangel, and cause this proteinuria and rare familial megaloblastic anemia type 1 ( mgÀ1 ).

Cubilin is found in tissues, which have an absorptive function, such as the intestinal epithelium, renal epithelium, Gallenepithel or in the yolk sac of the embryo. Cubilin binding to the outside of the membrane to transport proteins, lipids, calcidiol, cobalamin and transporting other substances, and holds these substances to the cell set. Then the cubilin complex is transported as vesicles inside the cell.

Function

Cubilin binds to the Intrinsic factor: cobalamin complex in the intestine, the Amnionless: cobalamin complex in the blood of immunoglobulin light chains, albumin and hemoglobin, the DBP: calcidiol complex, and apolipoprotein A1 and uteroglobin in the uterus. Cubilin forms with LRP1 and LRP2 ( megalin ) a complex. In any case, the calcium is needed for binding. Bind to megalin leads to endocytosis of the membrane section, and hence to accommodate all materials bound thereto in the cell. The cubilin: megalin complex may be also necessary to prevent gallstones.

Regulation

The activity and expression of megalin cubilin and is excited by tretinoin and is thus increased in dividing cells and cancer cells. Expressing cubilin in the kidneys is increased at the age, likely to compensate for the increase in the number of defects on the large protein.