Common elements in interleukin 4 and insulin signaling pathways in factor-dependent hematopoietic cells.
Interleukin 4 (IL-4), insulin, and insulin-like growth factor I (IGF-I) efficiently induced DNA synthesis in the IL-3-dependent murine myeloid cell lines FDC-P1 and FDC-P2. Although these factors could not individually sustain long-term growth of these lines, a combination of IL-4 with either insulin or IGF-I did support continuous growth. The principal tyrosine-phosphorylated substrate observed in FDC cells stimulated with IL-4, previously designated 4PS, was of the same size (170 kDa) as the major substrate phosphorylated in response to insulin or IGF-I. These substrates had phosphopeptides of the same size when analyzed by digestion with Staphylococcus aureus V8 protease, and each tightly associated with the 85-kDa component of phosphatidylinositol 3-kinase after factor stimulation. IRS-1, the principal substrate phosphorylated in response to insulin or IGF-I stimulation in nonhematopoietic cells, is similar in size to 4PS. However, anti-IRS-1 antibodies failed to efficiently precipitate 4PS, and some phosphopeptides generated by V8 protease digestion of IRS-1 were distinct in size from the phosphopeptides of 4PS. Nevertheless, IL-4, insulin, and IGF-I were capable of stimulating tyrosine phosphorylation of IRS-1 in FDC cells that expressed this substrate as a result of transfection. These findings indicate that (i) IL-4, insulin, and IGF-I use signal transduction pathways in FDC lines that have at least one major feature in common, the rapid tyrosine phosphorylation of 4PS, and (ii) insulin and IGF-I stimulation of hematopoietic cell lines leads to the phosphorylation of a substrate that may be related to but is not identical to IRS-1.
Wang
L M
LM
Laboratory of Cellular and Molecular Biology, National Cancer Institute, Bethesda, MD 20892.
Keegan
A D
AD
Li
W
W
Lienhard
G E
GE
Pacini
S
S
Gutkind
J S
JS
Myers
M G
MG
Sun
X J
XJ
White
M F
MF
Aaronson
S A
SA
D000818:Animals; D001773:Blood Cells; D016466:CHO Cells; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D006224:Cricetinae; D016895:Culture Media, Serum-Free; D004261:DNA Replication / Q000187:drug effects*; D004591:Electrophoresis, Polyacrylamide Gel; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D010449:Peptide Mapping; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism*; D010770:Phosphotransferases / Q000378:metabolism; D019000:Phosphotyrosine; D011972:Receptor, Insulin / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D013936:Thymidine / Q000378:metabolism; D014162:Transfection; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis
D016895:Culture Media, Serum-Free; D007328:Insulin; D007377:Interleukin-3; D010750:Phosphoproteins; D011994:Recombinant Proteins; D015847:Interleukin-4; D019000:Phosphotyrosine; D014443:Tyrosine; D007334:Insulin-Like Growth Factor I; D010770:Phosphotransferases; D019869:Phosphatidylinositol 3-Kinases; D011972:Receptor, Insulin; D013936:Thymidine