کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1927099 | 1536502 | 2007 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Effects of PKI55 protein, an endogenous protein kinase C modulator, on specific PKC isoforms activity and on human T cells proliferation Effects of PKI55 protein, an endogenous protein kinase C modulator, on specific PKC isoforms activity and on human T cells proliferation](/preview/png/1927099.png)
PKI55 protein, coded by the recently identified KI55 gene [R. Selvatici, E. Melloni, M. Ferrati, C. Piubello, F.C. Marincola, E. Gandini, J. Mol. Evol. 57 (2003) 131–139] is synthesized following protein kinase C (PKC) activation and acts as a PKC modulator, establishing a feedback loop of inhibition. In this work, PKI55 was found to inhibit recombinant α, β1, β2, γ, δ, ζ and η PKC isoforms; the effect on conventional PKC was lost in the absence of calcium. Confocal immunofluorescence experiments showed that PKI55 can penetrate into peripheral blood mononuclear cells (PBMC), following a coordinated movement of calcium ions. The addition of PKI55 protein down-regulated the PKC enzyme activity in phytohaemagglutinin-activated PBMC, decreasing the activity of α, β1 and β2 PKC isoforms. Moreover, inhibition in PBMC proliferation was observed. Similar effects were detected in Jurkat T cells transfected with a plasmid containing the coding sequence of PKI55. The PKI55 protein functional role could be to control the pathological over-expression of specific PKC isoforms and to regulate proliferation.
Journal: Archives of Biochemistry and Biophysics - Volume 462, Issue 1, 1 June 2007, Pages 74–82