Skip to main content
PMC home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1974 Dec;71(12):4732–4736. doi: 10.1073/pnas.71.12.4732

Selective Degradation of Abnormal Proteins in Mammalian Tissue Culture Cells

Mario R Capecchi 1, Nancy E Capecchi 1, Stephen H Hughes 1, Geoffrey M Wahl 1
PMCID: PMC433970  PMID: 4531013

Abstract

The degradation rates of several missense mutants of hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) in mouse L cells are compared to those of the wild-type enzyme. Although the rates of total protein breakdown in the mutant cell lines are identical to that of the parental L cell line, defective molecules of hypoxanthine-guanine phosphoribosyltransferase present in the mutant cell lines are degraded much faster than the wild-type enzyme. The level of defective phosphoribosyltransferase molecules present in the mutant cell lines is inversely proportional to the breakdown rate. This observation indicates that the major factor determining the concentrations of the defective phosphoribosyltransferases is their specific degradation rate. These results strongly support the hypothesis that abnormal proteins are selectively degraded in mammalian cells.

Keywords: protein degradation, hypoxanthine-guanine phosphoribosyltransferase, immunoprecipitation, somatic cell mutants

Full text

PDF
4732

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bukhari A. I., Zipser D. Mutants of Escherichia coli with a defect in the degradation of nonsense fragments. Nat New Biol. 1973 Jun 20;243(129):238–241. doi: 10.1038/newbio243238a0. [DOI] [PubMed] [Google Scholar]
  2. DeSimone J., Kleve L., Longley M. A., Shaeffer J. Rapid turnover of newly-synthesized beta S chains in reticulocytes from individuals with sickle cell trait. Biochem Biophys Res Commun. 1974 Mar 15;57(1):248–254. doi: 10.1016/s0006-291x(74)80383-9. [DOI] [PubMed] [Google Scholar]
  3. Goldberg A. L. Correlation between rates of degradation of bacterial proteins in vivo and their sensitivity to proteases. Proc Natl Acad Sci U S A. 1972 Sep;69(9):2640–2644. doi: 10.1073/pnas.69.9.2640. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Goldberg A. L. Degradation of abnormal proteins in Escherichia coli (protein breakdown-protein structure-mistranslation-amino acid analogs-puromycin). Proc Natl Acad Sci U S A. 1972 Feb;69(2):422–426. doi: 10.1073/pnas.69.2.422. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Goldberg A. L., Howell E. M., Li J. B., Martel S. B., Prouty W. F. Physiological significance of protein degradation in animal and bacterial cells. Fed Proc. 1974 Apr;33(4):1112–1120. [PubMed] [Google Scholar]
  6. Goldschmidt R. In vivo degradation of nonsense fragments in E. coli. Nature. 1970 Dec 19;228(5277):1151–1154. doi: 10.1038/2281151a0. [DOI] [PubMed] [Google Scholar]
  7. Gorini L., Beckwith J. R. Suppression. Annu Rev Microbiol. 1966;20:401–422. doi: 10.1146/annurev.mi.20.100166.002153. [DOI] [PubMed] [Google Scholar]
  8. Holliday R., Tarrant G. M. Altered enzymes in ageing human fibroblasts. Nature. 1972 Jul 7;238(5358):26–30. doi: 10.1038/238026a0. [DOI] [PubMed] [Google Scholar]
  9. Lewis C. M., Holliday R. Mistranslation and ageing in Neurospora. Nature. 1970 Nov 28;228(5274):877–880. doi: 10.1038/228877a0. [DOI] [PubMed] [Google Scholar]
  10. Lewis C. M., Tarrant G. M. Error theory and ageing in human diploid fibroblasts. Nature. 1972 Oct 6;239(5371):316–318. doi: 10.1038/239316a0. [DOI] [PubMed] [Google Scholar]
  11. Lin S., Zabin I. Beta-galactosidase. Rates of synthesis and degradation of incomplete chains. J Biol Chem. 1972 Apr 10;247(7):2205–2211. [PubMed] [Google Scholar]
  12. Orgel L. E. Ageing of clones of mammalian cells. Nature. 1973 Jun 22;243(5408):441–445. doi: 10.1038/243441a0. [DOI] [PubMed] [Google Scholar]
  13. Pine M. J. Response of intracellular proteolysis to alteration of bacterial protein and the implications in metabolic regulation. J Bacteriol. 1967 May;93(5):1527–1533. doi: 10.1128/jb.93.5.1527-1533.1967. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Pine M. J. Turnover of intracellular proteins. Annu Rev Microbiol. 1972;26:103–126. doi: 10.1146/annurev.mi.26.100172.000535. [DOI] [PubMed] [Google Scholar]
  15. Platt T., Miller J. H., Weber K. In vivo degradation of mutant lac repressor. Nature. 1970 Dec 19;228(5277):1154–1156. doi: 10.1038/2281154a0. [DOI] [PubMed] [Google Scholar]
  16. RABINOVITZ M., FISHER J. M. CHARACTERISTICS OF THE INHIBITION OF HEMOGLOBIN SYNTHESIS IN RABBIT RETICULOCYTES BY THREO-ALPHA-AMINO-BETA-CHLOROBUTYRIC ACID. Biochim Biophys Acta. 1964 Oct 16;91:313–322. doi: 10.1016/0926-6550(64)90255-5. [DOI] [PubMed] [Google Scholar]
  17. Shaeffer J. R. Structure and synthesis of the unstable hemoglobin Sabin (alpha 2 beta 2--91 Leu leads to pro). J Biol Chem. 1973 Nov 10;248(21):7473–7480. [PubMed] [Google Scholar]
  18. Sharp J. D., Capecchi N. E., Capecchi M. R. Altered enzymes in drug-resistant variants of mammalian tissue culture cells. Proc Natl Acad Sci U S A. 1973 Nov;70(11):3145–3149. doi: 10.1073/pnas.70.11.3145. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES