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The distribution of protein kinase C in human leukocytes is altered in microgravity
Author(s) -
Schmitt Didier A.,
Hatton Jason P.,
Emond Catherine,
Chaput Didier,
Paris HervÉ,
Levade Thierry,
Cazenave JeanPierre,
Schaffar Laurence
Publication year - 1996
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.10.14.9002555
Subject(s) - protein kinase c , cytosol , signal transduction , u937 cell , microbiology and biotechnology , jurkat cells , intracellular , chemistry , biochemistry , cell , biology , enzyme , in vitro , t cell , immunology , immune system
Protein kinase C (PKC) is an ubiqui‐tous enzyme that mediates intracellular signal transduction in eukaryotes. Jurkat and U937 cells were exposed to microgravity during a Space Shuttle flight and stimulated with a radiolabeled phorbol ester ( 3 H‐PDBu) that specifically activates and labels several PKC isoforms. Both the total amount of 3 H‐ PDBu labeling per cell and the relative distribution of labeling between subcellular compartments were altered in microgravity compared to onboard and ground 1 g control samples. The amount of total phorbol ester labeling per cell was increased ap‐proximately twofold in microgravity samples when compared with onboard 1 g samples for both cell lines. The subcellular distribution of PKC in the cytosol and nuclear fractions appeared to be correlated with the applied acceleration. In both cell types the relative amount of phorbol ester labeling in the nuclear fraction decreased with applied ac‐celeration, whereas the labeling in cytosolic fraction increased with g level. No significant differences were observed between labeling levels in the membrane fraction in both cell types. Interleukin‐ lβ synthesis by U937 cells was markedly decreased in microgravity when compared to the onboard 1 g control, suggesting that the observed alterations in PKC distribution may have functional consequences. The results may have important implications for the effect of gravity on cellular signal transduction.—Schmitt, D. A., Hatton, J. P., Emond, C., Chaput, D., Paris, H., Levade, T., Ca‐ zenave, J.‐P., Schaffar, L. The distribution of protein kinase C in human leukocytes is altered in microgravity. FASEB J. 10, 1627‐1634 (1996)