Post by Max on Jul 20, 2005 16:10:53 GMT -5
Transcription factor AP1 and AP2
AP1
AP2
Retinoids activate AP2 transcription factors [1 and more]. The AP2 transcription factor family is a set of developmentally regulated, retinoic acid inducible genes composed of four related factors, AP2alpha, AP2beta, AP2gamma, and AP2delta. AP2 factors orchestrate a variety of cell processes including apoptosis, cell growth, and tissue differentiation. AP2alpha targets the p53 tumor suppressor protein. Studies with chromatin immunoprecipitation demonstrate that AP2alpha is brought to p53 binding sites in p53-regulated promoters. The interaction between AP2alpha and p53 augments p53-mediated transcriptional activation, which results in up-regulation of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) [2].
Alkaline phosphatase causes redistribution of AP-2 subunits to cytosol due to dephosphorylation and detachment from membranes
In rat brain cell membranes, AP-2 á subunits are redistributed to the cytosol by exposure to alkaline phosphatase due to dephosphorylation of these proteins. The phosphorylation status of á1 and á2, before and after the exposure was measured using specific antibodies against either phosphorylated serine or tyrosine residue. Proteins phosphorylated in serine overlapped with both á subtypes, and underwent partial dephosphorylation by exposure to alkaline phosphatase. The rate of dephosphorylation may be related more to á2 than á1 detachment from the membranes. When samples were incubated with inhibitors of alkaline phosphatase, both subtypes were overphosphorylated.
Conclusion
(Ro)accutane upregulates AP2, constituting one pathway to inhibition of cyclin dependent kinases and translocation of p53.
AP1
AP2
Retinoids activate AP2 transcription factors [1 and more]. The AP2 transcription factor family is a set of developmentally regulated, retinoic acid inducible genes composed of four related factors, AP2alpha, AP2beta, AP2gamma, and AP2delta. AP2 factors orchestrate a variety of cell processes including apoptosis, cell growth, and tissue differentiation. AP2alpha targets the p53 tumor suppressor protein. Studies with chromatin immunoprecipitation demonstrate that AP2alpha is brought to p53 binding sites in p53-regulated promoters. The interaction between AP2alpha and p53 augments p53-mediated transcriptional activation, which results in up-regulation of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) [2].
Alkaline phosphatase causes redistribution of AP-2 subunits to cytosol due to dephosphorylation and detachment from membranes
In rat brain cell membranes, AP-2 á subunits are redistributed to the cytosol by exposure to alkaline phosphatase due to dephosphorylation of these proteins. The phosphorylation status of á1 and á2, before and after the exposure was measured using specific antibodies against either phosphorylated serine or tyrosine residue. Proteins phosphorylated in serine overlapped with both á subtypes, and underwent partial dephosphorylation by exposure to alkaline phosphatase. The rate of dephosphorylation may be related more to á2 than á1 detachment from the membranes. When samples were incubated with inhibitors of alkaline phosphatase, both subtypes were overphosphorylated.
Conclusion
(Ro)accutane upregulates AP2, constituting one pathway to inhibition of cyclin dependent kinases and translocation of p53.