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Cytoplasmic pH‐dependent spreading of polymorphonuclear leukocytes: Regulation by pH of PKC subcellular distribution and F‐actin assembly
Author(s) -
Suzuki Kingo,
Namiki Hideo
Publication year - 2007
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/j.cellbi.2006.11.005
Subject(s) - cytoplasm , cytoskeleton , microbiology and biotechnology , protein kinase c , actin , cell fractionation , actin cytoskeleton , subcellular localization , biology , biochemistry , chemistry , biophysics , cell , kinase , membrane
Cytoplasmic pH (pHi) plays an important role in the regulation of polymorphonuclear leukocyte (PMN) spreading, but the molecular mechanisms involved have long been obscure. In the present study, we investigated the pH‐dependence of phorbol myristate acetate (PMA)‐induced PMN spreading. A change in pHi alone did not induce spreading, but cytoplasmic alkalinization promoted the spreading induced by PMA, whereas acidification inhibited it. To further investigate the mechanism by which pHi affects cell spreading, we employed subcellular fractionation and immunoblot analyses to evaluate the effect of pH on the subcellular distribution of protein kinase C (PKC) and assembly of the actin cytoskeleton. We found that cytoplasmic alkalinization enhanced PKC membrane distribution and quantitatively up‐regulated the actin cytoskeleton. On the other hand, cytoplasmic acidification was found to have effects on these signaling molecules that were opposite to those of cytoplasmic alkalinization. These results may provide a potential explanation for the pH‐regulation of the PMA‐induced PMN spreading.