TY - JOUR
T1 - The insulin receptor functions normally in chinese hamster ovary cells after truncation of the C terminus
AU - Myers, Martin G.
AU - Backer, Jonathan M.
AU - Siddle, Kenneth
AU - White, Morris F.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1991
Y1 - 1991
N2 - We studied the structure and function of the human insulin receptor (IR) and a mutant which lacked the last 43 amino acids of the β-subunit (IRΔct). This deletion removed tyrosine (Tyr1322, Tyr1316) and threonine (Thr1336) phosphorylation sites. In Chinese hamster ovary (CHO) cells, insulin binding to the mutant receptor was normal, and [35S]methionine labeling indicated that both the IR and IRΔct were processed normally; however, the β-subunit of IRΔct was 5 kDa smaller than that of the IR. The time course of insulin-stimulated autophosphorylation of the partially purified IRΔct was normal, but the maximum autophosphorylation was reduced 20-30%. Tryptic phosphopeptide mapping confirmed the absence of the C-terminal phosphorylation sites and indicated that phosphorylation of the regulatory region (Tyr1146, Tyr1150, Tyr1151) occurred normally; kinase activity of the IR and IRΔct was activated normally by insulin-stimulated autophosphorylation. In the intact CHO cells, insulin-stimulated serine and threonine phosphorylation of the IRΔct was reduced 20%, suggesting that most Ser/Thr phosphorylation sites are located outside of the C terminus. During insulin stimulation, the wild-type and mutant insulin receptor activated the phosphatidylinositol 3-kinase. Moreover, insulin itself or human-specific antiinsulin receptor antibodies stimulated glycogen and DNA synthesis equally in both CHO/IR and CHO/IRΔct cells. These data suggest that the C terminus plays a minimal role in IR function and signal transmission in CHO cells.
AB - We studied the structure and function of the human insulin receptor (IR) and a mutant which lacked the last 43 amino acids of the β-subunit (IRΔct). This deletion removed tyrosine (Tyr1322, Tyr1316) and threonine (Thr1336) phosphorylation sites. In Chinese hamster ovary (CHO) cells, insulin binding to the mutant receptor was normal, and [35S]methionine labeling indicated that both the IR and IRΔct were processed normally; however, the β-subunit of IRΔct was 5 kDa smaller than that of the IR. The time course of insulin-stimulated autophosphorylation of the partially purified IRΔct was normal, but the maximum autophosphorylation was reduced 20-30%. Tryptic phosphopeptide mapping confirmed the absence of the C-terminal phosphorylation sites and indicated that phosphorylation of the regulatory region (Tyr1146, Tyr1150, Tyr1151) occurred normally; kinase activity of the IR and IRΔct was activated normally by insulin-stimulated autophosphorylation. In the intact CHO cells, insulin-stimulated serine and threonine phosphorylation of the IRΔct was reduced 20%, suggesting that most Ser/Thr phosphorylation sites are located outside of the C terminus. During insulin stimulation, the wild-type and mutant insulin receptor activated the phosphatidylinositol 3-kinase. Moreover, insulin itself or human-specific antiinsulin receptor antibodies stimulated glycogen and DNA synthesis equally in both CHO/IR and CHO/IRΔct cells. These data suggest that the C terminus plays a minimal role in IR function and signal transmission in CHO cells.
UR - http://www.scopus.com/inward/record.url?scp=0025786925&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025786925&partnerID=8YFLogxK
M3 - Article
C2 - 1645354
AN - SCOPUS:0025786925
SN - 0021-9258
VL - 266
SP - 10616
EP - 10623
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 16
ER -