Protein kinase C delta regulates anti-apoptotic alpha B-crystallin in the retina of type 2 diabetes

Abstract

We investigated the relationship between phosphorylation of alphaB-crystallin (alpha BC) and retinal apoptosis in type 2 diabetes. The retinas of male Otsuka Long-Evans Tokushima fatty (OLETF) rats at 24 and 35 weeks were used as an animal model for type 2 diabetes and sex- and age-matched Long-Evans Tokushima Otsuka (LETO) rats were used as controls. In the retinas of 35-week OLETF rats, the interaction between alpha BC and protein kinase C delta (PKC delta) among the PKC isozymes, alpha BC phosphorylation at Ser45 (S45p-alpha BC), TUNEL-positive apoptotic ganglion cells, several apoptotic signs, and colocalization of S45p-alpha BC and TUNEL significantly increased as compared with other groups while the alpha BC-Bax interaction greatly decreased. These changes were abolished by rottlerin treatment, a highly specific PKC 6 inhibitor. These results suggest that PKC 6 is involved in regulation of anti-apoptotic function of alpha BC in the retina of type 2 diabetes. (C) 2007 Elsevier Inc. All rights reserved.