Role of α-crystallin B in regulation of stress induced cardiomyocyte apoptosis.

Cardiovascular disease is the leading cause of death worldwide. Recently emerging evidence suggests that cardiomyocyte apoptosis is one of the major pathogenic factors in heart diseases leading to heart failure. Cardiomyocytes undergo apoptosis in response to a wide variety of cellular stresses including protein folding stress at Endoplasmic reticulum (ER). Stressed myocytes elicit an adaptive response referred as Unfolded Protein Response (UPR) by inducing accumulation of heat shock proteins (HSPs) to mitigate the ER stress. HSPs act as molecular chaperons by assisting correct folding of the aggregated misfolded proteins in ER lumen. α-Crystallin B (CRYAB) is an abundant small HSP that confers protection to cardiomyocytes against various stress stimuli. Recent evidence indicates that CRYAB directly interacts with several components of ER stress and also mitochondrial apoptotic pathway. Based on currently available literature this mini review will focus on how CRYAB confers protection to stressed myocardium thereby emphasizing its function as antiapoptotic molecule. Understanding the interplay between CRYAB and the key components in the apoptotic signaling cascade mediated by ER and mitochondria will help in development of novel therapies for cardiac diseases.