Editors' ChoiceDegradation

Compartmentalized Destruction

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Science's STKE  19 Dec 2000:
Vol. 2000, Issue 63, pp. tw3
DOI: 10.1126/stke.2000.63.tw3

Regulated proteolysis is important for proper control of many signal transduction pathways. Lenk and Sommer report that the turnover of the yeast transcriptional repressor MATα2 is controlled through the Deg1 degradation signal by virtue of its translocation into the nucleus. The subcellular distribution and half-life of a fusion protein between the Deg1 domain and green fluorescent protein with or without a nuclear localization or nuclear export signal was analyzed in wild-type and mutant yeast defective in nuclear transport. The half-life of the fusion protein depended on the ability of the fusion protein to accumulate in the nucleus and required the ubiquitin-conjugating enzymes Ubc6p and Ubc7p. The data suggest that there is nuclear-specific activity of components of the ubiquitin-proteasome degradation system and that the subcellular trafficking of a signaling molecule influences its degradation by this machinery.

Lenk, U., and Sommer, T. (2000) Ubiquitin-mediated proteolysis of a short-lived regulatory protein depends on its cellular localization. J. Biol. Chem. 275: 39403-39410. [Abstract] [Full Text]