Insulin resistance and growth retardation in mice lacking insulin receptor substrate-1.
Insulin receptor substrate-1 (IRS-1) is the major substrate of insulin receptor and IGF-1 receptor tyrosine kinases; it has an apparent relative molecular mass of 160-190,000 (M(r), 160-190K) on SDS polyacrylamide gel. Tyrosine-phosphorylated IRS-1 binds the 85K subunit of phosphatidylinositol 3-kinase which may be involved in the translocation of glucose transporters and the abundant src homology protein (ASH)/Grb2 which may be involved in activation of p21ras and MAP kinase cascade. IRS-1 also has binding sites for Syp and Nck and other src homology 2 (SH2) signalling molecules. To clarify the physiological roles of IRS-1 in vivo, we made mice with a targeted disruption of the IRS-1 gene locus. Mice homozygous for targeted disruption of the IRS-1 gene were born alive but were retarded in embryonal and postnatal growth. They also had resistance to the glucose-lowering effects of insulin, IGF-1 and IGF-2. These data suggest the existence of both IRS-1-dependent and IRS-1-independent pathways for signal transduction of insulin and IGFs.
Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
H
H
Tamemoto
T
T
Kadowaki
K
K
Tobe
T
T
Yagi
H
H
Sakura
T
T
Hayakawa
Y
Y
Terauchi
K
K
Ueki
Y
Y
Kaburagi
S
S
Satoh
D000818:Animals; D001483:Base Sequence; D001786:Blood Glucose / Q000378:metabolism; D005260:Female; D005317:Fetal Growth Retardation / Q000503:physiopathology; D006128:Growth / Q000502:physiology*; D006130:Growth Disorders / Q000503:physiopathology; D006579:Heterozygote; D006720:Homozygote; D007328:Insulin / Q000502:physiology*; D055504:Insulin Receptor Substrate Proteins; D007333:Insulin Resistance / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000502:physiology; D007335:Insulin-Like Growth Factor II / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000172:deficiency / Q000502:physiology*; D011972:Receptor, Insulin / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*
D001786:Blood Glucose; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D010750:Phosphoproteins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D011972:Receptor, Insulin