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The kinetics of translocation and cellular quantity of protein kinase C in human leukocytes are modified during spaceflight
Author(s) -
Hatton Jason P.,
Gaubert Francois,
Lewis Marian L.,
Darsel Yann,
Ohlmann Philippe,
Cazenave JeanPierre,
Schmitt Didier
Publication year - 1999
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.13.9001.s23
Subject(s) - hypergravity , protein kinase c , chromosomal translocation , cytosol , microbiology and biotechnology , kinase , chemistry , signal transduction , serine , phosphorylation , biology , biochemistry , enzyme , astrobiology , gene
Protein kinase C (PKC) is a family of serine/threonine kinases that play an important role in mediating intracellular signal transduction in eukaryotes. U937 cells were exposed to microgravity during a space shuttle flight and stimulated with a radiolabeled phorbol ester ([ 3 H]PDBu) to both specifically label and activate translocation of PKC from the cytosol to the particulate fraction of the cell. Although significant translocation of PKC occurred at all g levels, the kinetics of translocation in flight were significantly different from those on the ground. In addition, the total quantity of [ 3 H]PDBu binding PKC was increased in flight compared to cells at 1 g on the ground, whereas the quantity in hypergravity (1.4 g ) was decreased with respect to 1 g . Similarly, in purified human peripheral blood T cells the quantity of PKCδ varied in inverse proportion to the g level for some experimental treatments. In addition to these novel findings, the results confirm earlier studies which showed that PKC is sensitive to changes in gravitational acceleration. The mechanisms of cellular gravisensitivity are poorly understood but the demonstrated sensitivity of PKC to this stimulus provides us with a useful means of measuring the effect of altered gravitylevels on early cell activation events.—Hatton, J. P., Gaubert, F., Lewis, M. L., Darsel, Y., Ohlmann, P., Cazenave, J.‐P., Schmitt, D. The kinetics of translocation and cellular quantity of protein kinase C in human leukocytes are modified during spaceflight. FASEB J. 13 (Suppl.), S23–S33 (1999)