The tails of ubiquitin precursors are ribosomal proteins whose fusion to ubiquitin facilitates ribosome biogenesis.
Three of the four yeast ubiquitin genes encode hybrid proteins which are cleaved to yield ubiquitin and previously unidentified ribosomal proteins. The transient association between ubiquitin and these proteins promotes their incorporation into nascent ribosomes and is required for efficient ribosome biogenesis. These results suggest a novel 'chaperone' function for ubiquitin, in which its covalent association with other proteins promotes the formation of specific cellular structures.
Finley
D
D
Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, Massachusetts 02115.
Bartel
B
B
Varshavsky
A
A
D015152:Blotting, Northern; D005816:Genetic Complementation Test; D009154:Mutation; D011498:Protein Precursors / Q000235:genetics*; D012269:Ribosomal Proteins / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014452:Ubiquitins / Q000235:genetics*
D011498:Protein Precursors; D012269:Ribosomal Proteins; D014452:Ubiquitins