Cell protein degradation in cultured rat embryo fibroblasts suppression by vinblastine of the enhanced proteolysis by serum-deficient media

doi:10.1016/0304-4165(76)90146-X

Biochimica et Biophysica Acta (BBA) - General Subjects

Volume 451, Issue 2, 21 December 1976, Pages 511-516

https://doi.org/10.1016/0304-4165(76)90146-X Get rights and content

Abstract

Rat embryo fibroblasts grown in Eagle's minimal essential medium with 10% serum were labeled with L-[¹⁴C]leucine. After a 24 h cold chase, rates of proteolysis were evaluated by measuring the appearance of trichloroacetic acid-soluble ¹⁴C in the media. Cells remaining in minimal essential medium with 10% serum (basal) showed a proteolysis rate of 1% per h, whereas cells placed in minimal essential medium alone (serum-deficient) showed a stimulation of proteolysis to 3–4% per h. This enhanced proteolysis was transitory, occuring only for the first 4–8 h after cells were placed in the serum-deficient media. Vinblastine 10⁻⁵ M inhibited the enhanced proteolysis 40% but had no effect on basal proteolysis. Control experiments showed no detectable hydrolysis of extracellular proteins, nor did vinblastine affect the rate of protein synthesis. These data suggest that basal and enhanced proteolysis have at least partially distinct mechanisms in the cell and that only enhanced proteolysis involves microtubules.

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Cell protein degradation in cultured rat embryo fibroblasts suppression by vinblastine of the enhanced proteolysis by serum-deficient media

Abstract

Biochim. Biophys. Acta

Exptl. Cell Res.

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

Ann. Rev. Biochem.

J. Cell Biol.

Nature

Lab Invest.