Ubiquitin dependence of selective protein degradation demonstrated in the mammalian cell cycle mutant ts85

Cell. 1984 May;37(1):57-66. doi: 10.1016/0092-8674(84)90300-3.

Abstract

We have shown that covalent conjugation of ubiquitin to proteins is temperature-sensitive in the mouse cell cycle mutant ts85 due to a specifically thermolabile ubiquitin-activating enzyme (accompanying paper). We show here that degradation of short-lived proteins is also temperature sensitive in ts85 , in contrast to wild-type and revertant cells. While more than 70% of the prelabeled abnormal proteins (containing amino acid analogs) or puromycyl peptides are degraded within 4 hr at the permissive temperature in both ts85 and wild-type cells, less than 15% are degraded in ts85 cells at the nonpermissive temperature. Degradation of abnormal proteins and puromycyl peptides in both ts85 cells and wild-type cells is nonlysosomal and ATP-dependent. Immunochemical analysis shows a strong and specific reduction in the levels of in vivo labeled ubiquitin-protein conjugates at the nonpermissive temperature in ts85 cells. Degradation of normal, short-lived proteins is also specifically temperature sensitive in ts85 . We suggest that the contribution of ubiquitin-independent pathways to the degradation of short-lived proteins in this higher eucaryotic cell is no more than 10%, and possibly less.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Cell Cycle*
  • Cell Line
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Female
  • Kinetics
  • Mammary Neoplasms, Experimental / physiopathology
  • Mice
  • Mutation*
  • Neoplasm Proteins / isolation & purification
  • Neoplasm Proteins / metabolism*
  • Nucleoproteins / metabolism*
  • Temperature
  • Ubiquitins

Substances

  • Chromosomal Proteins, Non-Histone
  • Neoplasm Proteins
  • Nucleoproteins
  • Ubiquitins
  • Adenosine Triphosphate