Insulin-induced cell cycle progression is impaired in chinese hamster ovary cells overexpressing insulin receptor substrate-3.
To analyze the roles of insulin receptor substrate (IRS) proteins in insulin-stimulated cell cycle progression, we examined the functions of rat IRS-1 and IRS-3 in Chinese hamster ovary cells overexpressing the human insulin receptor. In this type of cell overexpressing IRS-1 or IRS-3, we showed that: 1) overexpression of IRS-3, but not IRS-1, suppressed the G1/S transition induced by insulin; 2) IRS-3 was more preferentially localized to the nucleus than IRS-1; 3) phosphorylation of glycogen synthase kinase 3 and MAPK/ERK was unaffected by IRS-3 overexpression, whereas that of protein kinase B was enhanced by either IRS; 4) overexpressed IRS-3 suppressed cyclin D1 expression in response to insulin; 5) among the signaling molecules regulating cyclin D1 expression, activation of the small G protein Ral was unchanged, whereas insulin-induced gene expression of c-myc, a critical component for growth control and cell cycle progression, was suppressed by overexpressed IRS-3; and 6) insulin-induced expression of p21, a cyclin-dependent kinase inhibitor, was decreased by overexpressed IRS-3. These findings imply that: 1) IRS-3 may play a unique role in mitogenesis by inhibiting insulin-stimulated cell cycle progression via a decrease in cyclin D1 and p21 expressions as well as suppression of c-myc mRNA induction in a manner independent of the activation of MAPK, protein kinase B, glycogen synthase kinase 3 and Ral; and 2) the interaction of IRS-3 with nuclear proteins may be involved in this process.
Kaburagi
Yasushi
Y
Department of Metabolic Disorder, Research Institute, International Medical Center of Japan, Shinjuku-ku, Tokyo 162-8655, Japan. kaburagi@ri.imcj.go.jp
Yamashita
Ryo
R
Ito
Yuzuru
Y
Okochi
Hitoshi
H
Yamamoto-Honda
Ritsuko
R
Yasuda
Kazuki
K
Sekihara
Hisahiko
H
Sasazuki
Takehiko
T
Kadowaki
Takashi
T
Yazaki
Yoshio
Y
D000818:Animals; D042846:CDC2-CDC28 Kinases / Q000235:genetics; D016466:CHO Cells; D018797:Cell Cycle Proteins / Q000235:genetics; D002455:Cell Division / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism; D006224:Cricetinae; D019938:Cyclin D1 / Q000235:genetics; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000235:genetics; D015870:Gene Expression; D016259:Genes, myc / Q000502:physiology; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D055504:Insulin Receptor Substrate Proteins; D020935:MAP Kinase Signaling System / Q000187:drug effects; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D016160:Retinoblastoma Protein / Q000378:metabolism; D020725:ral GTP-Binding Proteins / Q000378:metabolism
C493958:Cdkn1a protein, rat; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D007004:Hypoglycemic Agents; C526292:IRS1 protein, human; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526296:Irs1 protein, rat; C491584:Irs3 protein, rat; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D016160:Retinoblastoma Protein; D019938:Cyclin D1; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D042846:CDC2-CDC28 Kinases; C495892:Cdk2 protein, rat; C495903:Cdk4 protein, rat; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases; D038362:Glycogen Synthase Kinase 3; D020725:ral GTP-Binding Proteins