Molecular events triggered by heat shock in Y1 adrenocortical cells.
Several stimuli, including stress conditions, promote the activation of MAP kinases family members (ERK1/2, JNK, p38). In turn, these enzymes regulate several cellular functions. Given that MAPK activation requires the phosphorylation of these proteins, their inactivation depends on the activity of specific phosphatases. MAPK phosphatase-1 (MKP-1), a phosphatase specifically involved in the inactivation of MAPK family members, is induced by mitogenic stimuli and stress conditions. Here we describe the effect of heat shock (HS), 10 min, 45 degrees C, on MAPKs activities and MKP-1 mRNA and protein levels in Y1 adrenocortical cells. Western blot analysis performed with antibodies against the phosphorylated forms of ERK1/2 and JNK revealed that HS produced the rapid activation of these kinases. Their inactivation was also a rapid event and occurred together with the increase of MKP-1 protein levels detected by Western blot analysis. In addition, the effect of HS on MKP-1 protein levels seems to be exerted at the transcriptional level, since the amount of its mRNA in heat shocked cells was higher than in nonheated cells. Comparison of the temporal profiles of MKP-1 protein induction and MAPKs phospho-dephosphorylation suggests that MKP-1 induction could contribute to ERK1/2 and JNK inactivation after HS.
Gorostizaga
A
A
School of Medicine, University of Buenos Aires, Buenos Aires, Argentina.
Brion
L
L
Maloberti
P
P
Poderoso
C
C
Podestá
E J
EJ
Cornejo Maciel
F
F
Paz
C
C
D000302:Adrenal Cortex / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D054638:Dual Specificity Phosphatase 1; D004789:Enzyme Activation; D018882:Heat Stress Disorders / Q000378:metabolism*; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012769:Shock / Q000378:metabolism; D013997:Time Factors
D018797:Cell Cycle Proteins; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D020928:Mitogen-Activated Protein Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D054638:Dual Specificity Phosphatase 1; C517020:Dusp1 protein, mouse; D017027:Protein Tyrosine Phosphatases