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The Ubiquitin System in Higher and Lower Plants — Pathways in Protein Metabolism
Author(s) -
Pollmann Lutz,
Wettern Michael
Publication year - 1989
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1989.tb00063.x
Subject(s) - ubiquitin , proteolysis , protein turnover , protein degradation , biology , microbiology and biotechnology , ubiquitin conjugating enzyme , f box protein , biochemistry , ubiquitins , ubiquitin ligase , protein biosynthesis , gene , enzyme
The multiple biological functions of the small polypeptide ubiquitin are mirrored by its unparalleled conservation on the amino acid and gene organization level. During the last years, it has become widely accepted that ubiquitin is an essential component in the ATP‐dependent nonlysosomal protein degradation pathway occurring in all eukaryotic organisms. As turnover, consisting of protein synthesis and disassembly, is a central and vital process for each living cell, ubiquitin‐mediated proteolysis is of enormous physiological value. The components of the ubiquitin ligation system have been characterized skillfully in plant and animal cells, but at the moment many questions remain as to how the high degree of specificity that is necessary for the regulation of intracellular breakdown is ensured. The recent hypotheses and models proposed for the basic mechanisms of protein recognition, conjugation and degradation will be discussed in detail. The existence of ubiquitin‐protein conjugates which are not rapidly degraded clearly suggested that the role of ubiquitin is not restricted in its implication for protein turnover. Alterations of DNA structure, specific cell recognition mechanisms and cytoskeletal variations were observed as further ubiquitin‐dependent processes which are not directly coupled to protein degradation.