TY - JOUR
T1 - Regulation of Endogenous SH2 Domain-Containing Inositol 5-Phosphatase (SHIP2) in 3T3-L1 and Human Preadipocytes
AU - Gagnon, Annemarie
AU - Artemenko, Yulia
AU - Crapper, Thet
AU - Sorisky, Alexander
PY - 2003/11
Y1 - 2003/11
N2 - The role of the inositol lipid 5-phosphatase (SHIP2) in preadipocyte signaling is not known. Although overexpression of SHIP2 inhibited proliferation and 3H-thymidine incorporation in 3T3-L1 preadipocytes, there was no effect on insulin-induced adipogenesis. Insulin promoted SHIP2 tyrosine phosphorylation in differentiated 3T3-L1 adipocytes, but did not do so in preadipocytes. The absence of SHIP2 tyrosine phosphorylation suggests a potential explanation for the isolated rise in PI(3,4,5)P3, without any changes in PI(3,4)P2, previously observed following insulin treatment of these cells. Lack of SHIP2 tyrosine phosphorylation by insulin was also observed in primary cultures of human abdominal subcutaneous preadipocytes. These cells also produced PI(3,4,5)P3, but not PI(3,4)P2, in response to insulin. Comparison of insulin vs. PDGF treatment on SHIP2 tyrosine phosphorylation in 3T3-L1 and human preadipocytes revealed that only PDGF, which stimulates the accumulation of PI(3,4,5)P3 as well as PI(3,4)P2, was active in this regard, and only PDGF promoted the association of 52 kDa form of Shc with SHIP2. Nevertheless, both insulin and PDGF were equally effective in translocating SHIP2 to the plasma membrane in 3T3-L1 preadipocytes. Lack of SHIP2 tyrosine phosphorylation may account for the insulin-specific inositol phospholipid pattern of accumulation in preadipocytes.
AB - The role of the inositol lipid 5-phosphatase (SHIP2) in preadipocyte signaling is not known. Although overexpression of SHIP2 inhibited proliferation and 3H-thymidine incorporation in 3T3-L1 preadipocytes, there was no effect on insulin-induced adipogenesis. Insulin promoted SHIP2 tyrosine phosphorylation in differentiated 3T3-L1 adipocytes, but did not do so in preadipocytes. The absence of SHIP2 tyrosine phosphorylation suggests a potential explanation for the isolated rise in PI(3,4,5)P3, without any changes in PI(3,4)P2, previously observed following insulin treatment of these cells. Lack of SHIP2 tyrosine phosphorylation by insulin was also observed in primary cultures of human abdominal subcutaneous preadipocytes. These cells also produced PI(3,4,5)P3, but not PI(3,4)P2, in response to insulin. Comparison of insulin vs. PDGF treatment on SHIP2 tyrosine phosphorylation in 3T3-L1 and human preadipocytes revealed that only PDGF, which stimulates the accumulation of PI(3,4,5)P3 as well as PI(3,4)P2, was active in this regard, and only PDGF promoted the association of 52 kDa form of Shc with SHIP2. Nevertheless, both insulin and PDGF were equally effective in translocating SHIP2 to the plasma membrane in 3T3-L1 preadipocytes. Lack of SHIP2 tyrosine phosphorylation may account for the insulin-specific inositol phospholipid pattern of accumulation in preadipocytes.
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U2 - 10.1002/jcp.10367
DO - 10.1002/jcp.10367
M3 - Article
C2 - 14502564
AN - SCOPUS:0242348813
SN - 0021-9541
VL - 197
SP - 243
EP - 250
JO - Journal of Cellular Physiology
JF - Journal of Cellular Physiology
IS - 2
ER -