In vitro study of proteolytic degradation of rat histidine decarboxylase

Eur J Biochem. 2000 Mar;267(5):1527-31. doi: 10.1046/j.1432-1327.2000.01153.x.

Abstract

Mammalian ornithine decarboxylase (ODC) is a very unstable protein which is degraded in an ATP-dependent manner by proteasome 26S, after making contact with the regulatory protein antizyme. PEST regions are sequences described as signals for protein degradation. The C-terminal PEST region of mammalian ODC is essential for its degradation by proteasome 26S. Mammalian histidine decarboxylase (HDC) is also a short-lived protein. The full primary sequence of mammalian HDC contains PEST-regions at both the N- and C-termini. Rat ODC and different truncated and full versions of rat HDC were expressed in vitro. In vitro degradation of rat ODC and rat 1-512 HDC were compared. Like ODC, rat 1-512 HDC is degraded mainly by an ATP-dependent mechanism. However, antizyme has no effect on the degradation of 1-512 HDC. The use of the inhibitors MG-132 and lactacystine significantly inhibited the degradation of 1-512 HDC, suggesting that a ubiquitin-dependent, proteasome 26S proteolytic pathway is involved. Results obtained with the different modifications of rat HDC containing all three PEST regions (full version, 1-656 HDC), only the N-terminal PEST region (1-512 HDC), or no PEST region (69-512 HDC), indicate that the N-terminal (1-69) fragment, but not the C-terminal fragment, determines that the HDC protein is a proteasome substrate in vitro.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Histidine Decarboxylase / metabolism*
  • Hydrolysis
  • Rats
  • Recombinant Proteins / metabolism

Substances

  • Recombinant Proteins
  • Adenosine Triphosphate
  • Histidine Decarboxylase