Effects of PKI55 protein, an endogenous protein kinase C modulator, on specific PKC isoforms activity and on human T cells proliferation
| Autor: | Susanna Spisani, Sofia Falzarano, Anna Siniscalchi, Lara Franceschetti, Rita Selvatici |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Time Factors
T-Lymphocytes Biophysics chemistry.chemical_element Endogeny PKI55 Kinase inhibitor PKC isoforms Immune complex assay PBMC Jurkat cells Confocal microscopy Cell proliferation Calcium Biology Lymphocyte Activation PKC alpha Biochemistry Peripheral blood mononuclear cell Cell Adhesion Humans Protein Isoforms Cloning Molecular Molecular Biology Protein Kinase C Protein kinase C Microscopy Confocal Cell growth Cell Membrane Proteins Transfection Molecular biology Recombinant Proteins Cell biology chemistry Leukocytes Mononuclear |
| Zdroj: | Archives of Biochemistry and Biophysics. 462:74-82 |
| ISSN: | 0003-9861 |
| Popis: | 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 alpha, beta(1), beta(2), gamma, delta, zeta and eta 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 alpha, beta(1) and beta(2) 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect