Insulin rapidly stimulates ERK2 in the membrane of osteoblast-like UMR-106 cell.
We investigated subcellular distribution of ERK2 in osteoblast-like UMR-106 cell and explored to determine if its activities are regulated by insulin. 23%, 34% and 43% of total ERK2 were distributed in membrane, cytosol and nucleus, respectively. Insulin caused 40% increase of ERK2 content in membrane in 10 min whereas it induced approximately 50% decrease of ERK2 in cytosol in 10 min. In terms of kinase activity, insulin stimulated phosphorylation of the membrane-associated ERK2 by 2-fold and 1.8-fold in 1 min and 10 min and cytosolic ERK2 by 2.7-fold and 2.3-fold in 1 min and 10 min, respectively. In contrast, the phosphorylation of nuclear ERK2 was stimulated by insulin in time-dependent manner with maximal (3-fold) activity observed at 30 min. Insulin also increased the content of MEK2 in membrane by 2.2- to 2.6-fold in 10 min. MEK2 translocated into membrane in response to insulin may play a role in the activation of the membrane-associated ERK2 via phosphorylation.
Kim
S J
SJ
Department of Pharmacology, School of Dentistry, Kyung-Hee University Seoul, Korea.
Kim
K H
KH
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000187:drug effects* / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology; D007328:Insulin / Q000494:pharmacology*; D048370:MAP Kinase Kinase 2; D019950:Mitogen-Activated Protein Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology*; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000187:drug effects / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D013347:Subcellular Fractions / Q000187:drug effects / Q000201:enzymology; D014407:Tumor Cells, Cultured
D007328:Insulin; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases