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Title: Involvement of PKC{alpha} in insulin-induced PKC{delta} expression: Importance of SP-1 and NF{kappa}B transcription factors

Abstract

Protein kinase C delta (PKC{delta}) is a key molecule in insulin signaling essential for insulin-induced glucose transport in skeletal muscle. Recent studies in our laboratory have shown that insulin rapidly stimulates PKC{delta} activity and increases PKC{delta} protein and RNA levels, and that the SP-1 transcription factor is involved in insulin-induced transcription of the PKC{delta} gene. Activation of SP-1 involves serine phosphorylation and translocation to the nucleus. In this study we examined the possibility that PKC{alpha} might be involved in serine phosphorylation and activation of SP-1. We found that insulin rapidly phosphorylates and translocates SP-1. In the cytoplasm, SP-1 was constitutively associated with PKC{alpha}, and insulin stimulation caused these proteins to dissociate. In contrast, in the nucleus insulin induced an increase in association between PKC{alpha} and SP-1. PKC{alpha} inhibition blocked insulin-induced serine phosphorylation of SP-1 and its association with PKC{alpha} in the nucleus. Inhibition of PKC{alpha} also reduced the insulin-induced increase in PKC{delta} RNA and protein in the cytoplasmic and nuclear fractions. We also attempted to determine if another transcription factor might be involved in regulation of PKC{delta} expression. We earlier showed that insulin did not affect nuclear NF{kappa}B levels. Inhibition of NF{kappa}B, however, increased insulin-induced increase in PKC{delta} RNA andmore » protein in the cytoplasmic and nuclear fractions. Surprisingly, this inhibition reduced the insulin-induced increase in cytoplasmic and nuclear PKC{alpha} RNA and protein. Inhibition of PKC{delta} reduced I{kappa}B{alpha} phosphorylation as well as NF{kappa}B activation. Thus, PKC{alpha} regulates insulin-induced PKC{delta} expression levels and this regulation involves activation of SP-1 and NF{kappa}B.« less

Authors:
 [1];  [2]
  1. Faculty of Life Sciences, Department of Life Sciences, Bar-Ilan University, Ramat-Gan 52900 (Israel)
  2. Faculty of Life Sciences, Department of Life Sciences, Bar-Ilan University, Ramat-Gan 52900 (Israel). E-mail: sampsos@mail.biu.ac.il
Publication Date:
OSTI Identifier:
20857948
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 352; Journal Issue: 1; Other Information: DOI: 10.1016/j.bbrc.2006.10.149; PII: S0006-291X(06)02413-2; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; CYTOPLASM; GLUCOSE; INHIBITION; INSULIN; MOLECULES; MUSCLES; PHOSPHORYLATION; RNA; SERINE; STIMULATION; TRANSCRIPTION; TRANSCRIPTION FACTORS

Citation Formats

Horovitz-Fried, Miriam, and Sampson, Sanford R. Involvement of PKC{alpha} in insulin-induced PKC{delta} expression: Importance of SP-1 and NF{kappa}B transcription factors. United States: N. p., 2007. Web. doi:10.1016/j.bbrc.2006.10.149.
Horovitz-Fried, Miriam, & Sampson, Sanford R. Involvement of PKC{alpha} in insulin-induced PKC{delta} expression: Importance of SP-1 and NF{kappa}B transcription factors. United States. doi:10.1016/j.bbrc.2006.10.149.
Horovitz-Fried, Miriam, and Sampson, Sanford R. Fri . "Involvement of PKC{alpha} in insulin-induced PKC{delta} expression: Importance of SP-1 and NF{kappa}B transcription factors". United States. doi:10.1016/j.bbrc.2006.10.149.
@article{osti_20857948,
title = {Involvement of PKC{alpha} in insulin-induced PKC{delta} expression: Importance of SP-1 and NF{kappa}B transcription factors},
author = {Horovitz-Fried, Miriam and Sampson, Sanford R.},
abstractNote = {Protein kinase C delta (PKC{delta}) is a key molecule in insulin signaling essential for insulin-induced glucose transport in skeletal muscle. Recent studies in our laboratory have shown that insulin rapidly stimulates PKC{delta} activity and increases PKC{delta} protein and RNA levels, and that the SP-1 transcription factor is involved in insulin-induced transcription of the PKC{delta} gene. Activation of SP-1 involves serine phosphorylation and translocation to the nucleus. In this study we examined the possibility that PKC{alpha} might be involved in serine phosphorylation and activation of SP-1. We found that insulin rapidly phosphorylates and translocates SP-1. In the cytoplasm, SP-1 was constitutively associated with PKC{alpha}, and insulin stimulation caused these proteins to dissociate. In contrast, in the nucleus insulin induced an increase in association between PKC{alpha} and SP-1. PKC{alpha} inhibition blocked insulin-induced serine phosphorylation of SP-1 and its association with PKC{alpha} in the nucleus. Inhibition of PKC{alpha} also reduced the insulin-induced increase in PKC{delta} RNA and protein in the cytoplasmic and nuclear fractions. We also attempted to determine if another transcription factor might be involved in regulation of PKC{delta} expression. We earlier showed that insulin did not affect nuclear NF{kappa}B levels. Inhibition of NF{kappa}B, however, increased insulin-induced increase in PKC{delta} RNA and protein in the cytoplasmic and nuclear fractions. Surprisingly, this inhibition reduced the insulin-induced increase in cytoplasmic and nuclear PKC{alpha} RNA and protein. Inhibition of PKC{delta} reduced I{kappa}B{alpha} phosphorylation as well as NF{kappa}B activation. Thus, PKC{alpha} regulates insulin-induced PKC{delta} expression levels and this regulation involves activation of SP-1 and NF{kappa}B.},
doi = {10.1016/j.bbrc.2006.10.149},
journal = {Biochemical and Biophysical Research Communications},
number = 1,
volume = 352,
place = {United States},
year = {Fri Jan 05 00:00:00 EST 2007},
month = {Fri Jan 05 00:00:00 EST 2007}
}
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