Expression of mammalian protein kinase C in Schizosaccharomyces pombe: isotype-specific induction of growth arrest, vesicle formation, and endocytosis.
Mammalian protein kinase C (PKC) isotypes elicit a number of effects on expression in Schizosaccharomyces pombe. A small decrease in growth rate results from PKC-gamma expression, and treatment of these cells with phorbol esters leads to marked growth inhibition and vesicle formation. PKC-delta and -eta expression causes growth inhibition and vesiculation, and the magnitude of both of these effects is increased by phorbol esters. In contrast, PKC-epsilon expression produces growth inhibition but no vesicle accumulation, and this effect is not responsive to phorbol ester. Finally, PKC-zeta has no observable effect. Thus, isotype-specific biological effects are observed. The accumulation of vesicles correlates with phorbol ester-dependent growth inhibition and occurs only with expression of those isotypes that down-regulate in response to phorbol esters in these cells. Antibodies against mammalian clathrin light chain 1a identified clathrin-coated vesicles and up-regulation of clathrin expression in those cells where vesicles accumulate; the increased vesicular traffic includes an element of endocytosis. Thus expression of specific mammalian PKC isotypes up-regulates endocytosis in S. pombe, providing a likely explanation for PKC-mediated receptor internalization in higher eukaryotes.
Goode
N T
NT
Protein Phosphorylation Laboratory, Imperial Cancer Research Fund, London, United Kingdom.
Hajibagheri
M A
MA
Warren
G
G
Parker
P J
PJ
D000818:Animals; D002455:Cell Division; D003001:Cloning, Molecular; D004705:Endocytosis; D015870:Gene Expression; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism; D007546:Isoquinolines; D008854:Microscopy, Electron; D010641:Phenotype; D011493:Protein Kinase C / Q000235:genetics* / Q000378:metabolism; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014170:Transformation, Genetic
D007527:Isoenzymes; D007546:Isoquinolines; C017475:lucifer yellow; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate