Developmental expression of insulin receptor substrate-2 during dimethylsulfoxide-induced differentiation of human HL-60 cells.
Insulin receptor substrate-2 (IRS-2) is phosphorylated on tyrosine by a number of cytokine receptors and is implicated in the activation of phosphatidylinositol 3'-kinase (PI3-kinase). Here, we demonstrate that induction of granulocytic differentiation of human promyeloid HL-60 cells leads to an increase in the amount of IRS-2 that is phosphorylated in response to insulin-like growth factor (IGF)-I. Although PI3-kinase is often activated following interaction with IRS-1, we could not detect IRS-1 protein, IRS-1 mRNA, or IRS-1-precipitable PI3-kinase enzymatic activity. However, PI3-kinase activity that was coimmunoprecipitated with either anti-phosphotyrosine or anti-IRS-2 following IGF-I stimulation was increased 100-fold. Heightened tyrosine phosphorylation of IRS-2 during granulocytic differentiation was not caused by an increase in expression of the tyrosine kinase IGF-I receptor, as measured by the amount of both the alpha- and beta-subunits. Instead, immunoblotting experiments with an Ab to IRS-2 revealed that induction of granulocytic differentiation caused a large increase in IRS-2, and this occurred in the absence of detectable IRS-1 protein. These IRS-2-positive cells could not differentiate into more mature myeloid cells in serum-free medium unless IGF-I was added. These data are consistent with a model of granulocytic differentiation that requires at least two signals, the first of which leads to an increase in the cytoplasmic pool of IRS-2 protein and a second molecule that acts to tyrosine phosphorylate IRS-2 and enhance granulocytic differentiation.
Schacher
D H
DH
Laboratory of Immunophysiology, Department of Animal Sciences, College of Medicine, University of Illinois, Urbana 61801, USA.
VanHoy
R W
RW
Liu
Q
Q
Arkins
S
S
Dantzer
R
R
Freund
G G
GG
Kelley
K W
KW
D002454:Cell Differentiation / Q000187:drug effects; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D004306:Dose-Response Relationship, Immunologic; D004789:Enzyme Activation; D006098:Granulocytes / Q000166:cytology / Q000378:metabolism; D018922:HL-60 Cells / Q000166:cytology* / Q000378:metabolism*; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D055504:Insulin Receptor Substrate Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000276:immunology; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000096:biosynthesis; D017526:Receptor, IGF Type 1 / Q000096:biosynthesis; D011972:Receptor, Insulin / Q000096:biosynthesis*; D013379:Substrate Specificity; D014443:Tyrosine / Q000378:metabolism
C526292:IRS1 protein, human; C526297:IRS2 protein, human; D007106:Immune Sera; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D019000:Phosphotyrosine; D014443:Tyrosine; D007334:Insulin-Like Growth Factor I; D019869:Phosphatidylinositol 3-Kinases; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin; D004121:Dimethyl Sulfoxide