PHAS-I phosphorylation in response to foetal bovine serum (FBS) is regulated by an ERK1/ERK2-independent and rapamycin-sensitive pathway in 3T3-L1 adipocytes.
The phosphorylation state of PHAS-I is thought to be important in the regulation of protein synthesis initiation. PHAS-I phosphorylation significantly increases in response to growth factors and insulin. ERK1/ERK2 have previously been implicated as PHAS-I kinases. Present work utilised a specific phosphorothioate oligonucleotide antisense strategy against ERK1/ERK2 to determine whether ERK1/ERK2 mediate FBS-stimulated PHAS-I phosphorylation in vivo. Depleting > 90% of cellular ERK1/ERK2 had no effect on FBS-stimulated PHAS-I phosphorylation. However, treatment of cells with a specific p70S6k pathway inhibitor, rapamycin, markedly attenuated FBS-stimulated PHAS-I phosphorylation. These results indicate that PHAS-I phosphorylation in response to FBS occurs through an ERK1/ERK2-independent and rapamycin-sensitive pathway in 3T3-L1 adipocytes.
Arnott
C H
CH
Department of Biochemistry, School of Biological Sciences, Southampton, UK.
Atkinson
P G
PG
Sale
E M
EM
Sale
G J
GJ
D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D017667:Adipocytes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D000818:Animals; D001769:Blood; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002352:Carrier Proteins; D002417:Cattle; D018797:Cell Cycle Proteins; D039642:Eukaryotic Initiation Factors; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011090:Polyenes / Q000494:pharmacology*; D020123:Sirolimus
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C499527:Eif4ebp1 protein, mouse; D039642:Eukaryotic Initiation Factors; D010750:Phosphoproteins; D011090:Polyenes; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D020123:Sirolimus