Zn(2+)-transporter-8: a dual role in diabetes.

Diabetes mellitus arises from defects in insulin secretion or action, or both. In pancreatic islets, insulin production is linked with zinc transport mediated by zinc transporter ZnT-8, a product of the SLC30A8 gene. Therefore, altered activity of ZnT-8 is expected to be associated with impaired glucose-induced insulin response and promote progression from glucose intolerance to diabetes. Recent findings do emerge with a role of SLC30A8 in diabetes. Genome-wide association scans for type 2 diabetes (T2D) susceptibility loci revealed and then replicated a highly significant association between the R allele of the R325W variant of SLC30A8 (marker rs13266634) and susceptibility to T2D in Caucasians. A role of ZnT-8 as a new major self-antigenic determinant in type 1 diabetes (T1D) was found. Marker rs13266634 was also shown to modulate anti-ZnT-8 self-antibody specificity in islet autoimmunity. Hence, these findings suggest for a dual role of SLC30A8 in diabetes, which is consisted in conferring genetic susceptibility to T2D and being a major islet self-antigen in T1D as well. Here we characterize an emerging role of ZnT-8 in diabetes and discuss potential mechanisms of its involvement in the etiology of both forms of diabetes.