IRS-1 is a major insulin receptor substrate which may play an important role in insulin signal
transmission. The mRNA for IRS-1 in rat cells and tissues is about 9.5 kilobases (kb). Rat
liver IRS-1 was stably expressed in Chinese hamster ovary (CHO) cells (CHO/IRS-1).
Although its calculated molecular mass is 131 kDa, IRS-1 from quiescent cells migrated
between 165 and 170 kDa during sodium dodecyl sulfate-polyacrylamide gel
electrophoresis. IRS-1 was phosphorylated strongly on serine residues and weakly on …