Tsitologiya  2015  57 (6) : 405–414
NEW ACHIEVEMENTS IN THE STUDY OF THE MECHANISMS AND TARGETS OF ACTION OF PROINSULIN C-PEPTIDE

A.O. Shpakov

I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St. Petersburg, 194223, and St. Petersburg State University, 199034;
e-mail: alex_shpakov@list.ru

The Ñ-peptide, product of proinsulin proteolysis, is a chaperone for insulin during its storage in the transport vesicles of pancreatic β-cells and further after its secretion into the bloodstream. Along with this, C-peptide functions as endogenous regulator of a number of the intracellular effector proteins, including phospholipase Cβ, phosphatidylinositol 3-kinase, mitogen-activated protein kinases, non-receptor tyrosine kinases, and controls cAMP- and cGMP-dependent cascades. Recently, the specific receptor GPR146 for C-peptide, which belongs to the superfamily of G protein-coupled receptors, has been identified. The decrease in the C-peptide level and the activity of its signaling cascades in diabetes mellitus lead to a wide range of complications of this disease including diabetic nephropathy, cardiomyopathy, angiopathy, and neuropathy. The changes in C-peptide functions has been found in non-diabetic patients with cardiovascular system disorders and renal failure. This review is devoted to the most significant events in the exploration of structural and functional organization of the C-peptide molecule, the identification of its receptor, the study of the molecular mechanisms of its action on cells that have taken place over the last few years. This review focuses on the most significant events recent years in the study of structural-functional organization of C-peptide and the molecular mechanisms of its action on the cell.

Key words:  C-peptide, insulin, diabetes mellitus, receptor GPR146, phospholipase C, GTP-binding protein


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