Walleye dermal sarcoma virus Orf B functions through receptor for activated C kinase (RACK1) and protein kinase C

Cells transformed by the McDonough strain of feline sarcoma virus express at their surface a v-fms-specific transmembrane glycoprotein designated gp140v-fms. By labeling with 32Pi, gp140v-fms was shown to be phosphorylated 30-fold more in serine residues than were the cytosolic v-fms polypeptides gp180gag-fms and gp120v-fms. By using the phosphotyrosine phosphatase-specific inhibitor sodium orthovanadate, an additional tyrosine phosphorylation was observed in vivo, again involving predominantly gp140v-fms. In vitro studies showed that the v-fms proteins were phosphorylated by protein kinase C in a calcium- and phosphatidylserine-dependent manner.

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Activation of 6-phosphofructo-2-kinase by pp60v-src is an indirect effect

Biochemical Journal ◽

10.1042/bj2850413 ◽

1992 ◽

Vol 285 (2) ◽

pp. 413-417 ◽

Cited By ~ 9

Author(s):

M J Marchand ◽

L Maisin ◽

L Hue ◽

G G Rousseau

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Rous Sarcoma Virus ◽

Rna Synthesis ◽

Phorbol Esters ◽

Permissive Temperature ◽

Rous Sarcoma ◽

Kinase C ◽

Sarcoma Virus ◽

Temperature Pretreatment

6-Phosphofructo-2-kinase (PFK-2) catalyses the synthesis of fructose 2,6-bisphosphate (Fru-2,6-P2), a potent stimulator of glycolysis. In chick-embryo fibroblasts, PFK-2 activity and Fru-2,6-P2 concentration increase upon transformation by Rous sarcoma virus. We show here that the increase in PFK-2 activity required more than 2 h after shifting fibroblasts infected with a thermosensitive mutant of Rous sarcoma virus from the restrictive to the permissive temperature. Pretreatment of the cells with actinomycin D prevented this increase in PFK-2 activity, suggesting a requirement for RNA synthesis. However, the increase in PFK-2 activity did not correspond to an increase in immunoprecipitable PFK-2. Moreover, the thermostability of PFK-2 and the affinity of this enzyme for its substrate fructose 6-phosphate were increased upon transformation by Rous sarcoma virus. Staurosporine, an inhibitor of protein kinase C, prevented the increase in PFK-2 activity brought about by the shift to the permissive temperature. This, together with a comparison of the effects of phorbol esters on PFK-2 activity, suggests that pp60v-src stimulates, via protein kinase C, the transcription of a gene whose products is a distinct PFK-2 isoenzyme or a protein that activates PFK-2.

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gp140v-fms molecules expressed at the surface of cells transformed by the McDonough strain of feline sarcoma virus are phosphorylated in tyrosine and serine

Molecular and Cellular Biology ◽

10.1128/mcb.6.12.4745-4748.1986 ◽

1986 ◽

Vol 6 (12) ◽

pp. 4745-4748

Author(s):

T Tamura ◽

E Simon ◽

H Niemann ◽

G T Snoek ◽

H Bauer

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Specific Inhibitor ◽

Dependent Manner ◽

Sodium Orthovanadate ◽

Transmembrane Glycoprotein ◽

Kinase C ◽

Sarcoma Virus

Cells transformed by the McDonough strain of feline sarcoma virus express at their surface a v-fms-specific transmembrane glycoprotein designated gp140v-fms. By labeling with 32Pi, gp140v-fms was shown to be phosphorylated 30-fold more in serine residues than were the cytosolic v-fms polypeptides gp180gag-fms and gp120v-fms. By using the phosphotyrosine phosphatase-specific inhibitor sodium orthovanadate, an additional tyrosine phosphorylation was observed in vivo, again involving predominantly gp140v-fms. In vitro studies showed that the v-fms proteins were phosphorylated by protein kinase C in a calcium- and phosphatidylserine-dependent manner.

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