Faculty Research 1990 - 1999
Beta-cell lines derived from transgenic Cpe(fat)/Cpe(fat) mice are defective in carboxypeptidase E and proinsulin processing.
Document Type
Article
Publication Date
1997
Keywords
Blotting-Western, Carboxypeptidases: ge, me, Cell-Line, Enzyme-Precursors: me, Immunohistochemistry, Insulin: bi, Islets-of-Langerhans: cy, me, Mice, Mice-Inbred-C57BL, Mice-Inbred-NOD, Mice-Transgenic: ge, me, Microscopy-Electron, Point-Mutation, Proinsulin: me, Protein-Processing-Post-Translational: ph, Rats, SUPPORT-NON-U-S-GOVT, SUPPORT-U-S-GOVT-P-H-S
First Page
4883
Last Page
4892
JAX Source
Endocrinology 1997 Nov;138(11):4883-92
Grant
DK51271/DK/NIDDK, DA04494/DA/NIDA, DA00194/DA/NIDA
Abstract
A spontaneous point mutation in the coding region of the carboxypeptidase E (CPE) gene in Cpe(fat)/Cpe(fat) mice affects proinsulin processing. Cell lines derived from the pancreatic beta-cells of Cpe(fat)/Cpe(fat) mice were generated by crossing C57BLKS/J-Cpe(fat)/+ mice with NOD mice expressing the simian virus 40 large T oncogene under the control of the rat insulin II promoter. Two cell lines, designated NIT-2 and NIT-3, were cultured from adenomatous islets obtained from F2 littermates and were compared with the NIT-1 cell line previously developed from mice with wild-type CPE. Electron microscopy of the cultured NIT-2 and -3 cells showed increased numbers of enlarged and electron-lucent granules compared with NIT-1 cells. Pro-CPE, but not the mature form of CPE, is present in NIT-2 and -3 cells, and neither pro-CPE nor CPE are secreted into the medium. Immunocytochemistry shows the pro-CPE to be localized to an endoplasmic reticulum-like structure in NIT-3 cells. Proinsulin is less extensively processed in NIT-2 and -3 cells than in NIT-1 cells, indicating that the Cpe(fat) mutation affects both the endopeptidase and carboxypeptidase reactions. The secretion of insulin/proinsulin from NIT-2 and -3 cells is significantly elevated by secretagogues, indicating that CPE is not required for sorting proinsulin into the regulated pathway.
Recommended Citation
Varlamov O,
Fricker LD,
Furukawa H,
Steiner DF,
Langley SH,
Leiter EH.
Beta-cell lines derived from transgenic Cpe(fat)/Cpe(fat) mice are defective in carboxypeptidase E and proinsulin processing. Endocrinology 1997 Nov;138(11):4883-92