title: Inhibition of protein kinase C results in a switch from a non-motile to a motile phenotype in diverse human lymphocyte populations.
abstract: Circulating lymphocytes are rounded, non-motile cells which on contact with cytokines, specialized or activated endothelium, acquire a constantly shape-changing, polarized morphology which enables migration into appropriate sites. The biochemical mechanisms which regulate this switch are not understood but the various stimuli may have a common final pathway. In this study we show that protein kinase C (PKC) inhibitors of the bisindolylmaleimide type (GF 109203X, Ro 31-8220, CGP 41,251) induce resting, spherical lymphocytes to change rapidly (< 30 min) into polarized, locomotory cells. This phenomenon was seen with diverse populations of blood T lymphocytes, tonsillar B cells and Jurkat and Molt4 T-cell lines. Consistent with this, down-regulation of PKC by chronic treatment (44 hr) with bryostatin also induced the polarized phenotype in blood lymphocytes and non-motile Molt4 cells. Conversely, treatment of a spontaneously motile subline of Molt4 cells with various PKC activators caused a reversion to the non-motile phenotype within minutes. PKC activation must be sufficient to overcome the effects of a constitutively active phosphatase because bisindolylmaleimide induction of motility could be prevented by pretreatment of the cells with a phosphatase inhibitor, calyculin A. It is concluded that, in resting lymphocytes, chronic activation of a PKC offsets the action of a constitutively active phosphatase and the net result is maintenance of the non-motile state. Agents which alter the kinase/phosphatase balance in favour of dephosphorylation result in induction of the locomotory phenotype.
authors.affiliation: Yamanouchi Research Institute, Littlemore Hospital, Oxford, UK.
authors.forename: C
authors.initials: C
authors.lastname: Southern
authors.forename: P C
authors.initials: PC
authors.lastname: Wilkinson
authors.forename: K M
authors.initials: KM
authors.lastname: Thorp
authors.forename: L K
authors.initials: LK
authors.lastname: Henderson
authors.forename: M
authors.initials: M
authors.lastname: Nemec
authors.forename: N
authors.initials: N
authors.lastname: Matthews
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D001402:B-Lymphocytes / Q000201:enzymology; D015153:Blotting, Western; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004789:Enzyme Activation; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D008301:Maleimides / Q000494:pharmacology; D008387:Marine Toxins; D010080:Oxazoles / Q000494:pharmacology; D010641:Phenotype; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D019311:Staurosporine / Q000031:analogs & derivatives*; D013601:T-Lymphocytes / Q000201:enzymology
chemical_list: D000470:Alkaloids; D007211:Indoles; D008301:Maleimides; D008387:Marine Toxins; D010080:Oxazoles; C059041:calyculin A; D011493:Protein Kinase C; D010749:Phosphoprotein Phosphatases; D019311:Staurosporine; C059539:midostaurin; C070515:bisindolylmaleimide I; C064758:Ro 31-8220