Faculty Collaboration Database

Potential autoantigens in IDDM. Expression of carboxypeptidase-H and insulin but not glutamate decarboxylase on the beta-cell surface. Diabetes 1994 Mar;43(3):418-25

Date

03/01/1994

Pubmed ID

8314014

DOI

10.2337/diab.43.3.418

Scopus ID

2-s2.0-0028140001 (requires institutional sign-in at Scopus site)   30 Citations

Abstract

Insulin, carboxypeptidase-H (CP-H), and glutamate decarboxylase (GAD) have been identified as potential autoantigens in insulin-dependent diabetes mellitus (IDDM). Previous studies have described immunoreactive insulin as a surface molecule on the plasma membrane of rat islet cells and suggested that cell-surface insulin was derived during exocytosis by the fusion of insulin secretory granules with the beta-cell plasma membrane. These findings predict that insulin and other secretory granule-derived proteins such as the putative autoantigen CP-H may be colocalized with insulin at specific sites of exocytosis on the beta-cell surface. In studies to test this hypothesis, cell-surface staining of dispersed rat islet cells occurred in a granule-like pattern with antibodies for CP-H and insulin. The specificity of the CP-H antiserum was confirmed by immunoblotting and indicated that the antiserum was essentially monospecific for CP-H. Confocal laser microscopy confirmed that immunoreactive staining for CP-H and insulin was confined to the beta-cell surface. Colocalization of CP-H and insulin on the cell surface of beta-cells was demonstrated by double staining with antibodies to CP-H and insulin, and the percentage of beta-cells positive for both of these autoantigens increased twofold with increases in insulin secretion. In contrast, islet cells failed to reveal cell-surface staining for GAD65, another putative autoantigen in IDDM, under either basal or insulin stimulatory conditions or following exposure of islet cells to the cytokines interleukin-1 beta, tumor necrosis factor-alpha, and recombinant human interferon-gamma.(ABSTRACT TRUNCATED AT 250 WORDS)

Author List

Aguilar-Diosdado M, Parkinson D, Corbett JA, Kwon G, Marshall CA, Gingerich RL, Santiago JV, McDaniel ML

Author

John A. Corbett PhD Chair, Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Autoantigens
Carboxypeptidase H
Carboxypeptidases
Cell Membrane
Diabetes Mellitus, Experimental
Diabetes Mellitus, Type 1
Fluorescein-5-isothiocyanate
Fluorescent Antibody Technique
Fluorescent Dyes
Glutamate Decarboxylase
Immunoblotting
Insulin
Islets of Langerhans
Male
Rats
Rats, Sprague-Dawley