Work

Nm23-H1 Regulates Glucose-Stimulated Insulin Secretion in Pancreatic β-Cells via Arf6-Rac1 Signaling Axis

Year: 2013

Type: article

Abstract: BACKGROUND: A growing body of evidence implicates novel roles for nm23-like proteins in the regulation of cellular functions. However, roles of these proteins in islet function and glucose-stimulated insulin secretion (GSIS) remain largely unknown. METHODS: siRNA-nm23-H1 and nucleoside diphosphate kinase and histidine kinase-deficient mutants of nm23-H1 (K12Q and H118F) were used to assess roles of nm23-H1 in GSIS. RESULTS: siRNA-mediated knockdown of the expression of nm23-H1 markedly inhibited GSIS in INS-1 832/13 cells. Nm23-H1 knockdown also resulted in significant inhibition of glucose-mediated activation of Arf6, a small G-protein, which has been implicated in GSIS. Expression of K12Q and H118F mutants of nm23-H1 in INS-1 832/13 cells led to inhibition of glucose-induced translocation and membrane association of Rac1, another small G-protein, which is downstream to Arf6 in the signaling events leading to GSIS. A significant inhibition of GSIS was also seen in these cells expressing K12Q and H118F. CONCLUSIONS: We conclude that the nm23-H1 activation step is upstream of Arf6 activation in signaling events leading to GSIS. NDP kinase and histidine kinase functions of nm23-H1 are necessary for glucose-induced membrane association of Rac1 and ensuing insulin secretion. We present the first evidence for regulation of GSIS by nm23-H1 in pancreatic β-cells.

Source: Cellular Physiology and Biochemistry

DOI: 10.1159/000354457

Authors: Rajakrishnan Veluthakal, David Kaetzel, Anjaneyulu Kowluru

Institutions: Wayne State University, John D. Dingell VA Medical Center, University of Maryland, Baltimore

Language: English

Topic: Pancreatic function and diabetes

Subfield: Surgery

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $1,925