A multiubiquitin chain is confined to specific lysine in a targeted short-lived protein.

The ubiquitin-dependent degradation of a test protein beta-galactosidase (beta gal) is preceded by ubiquitination of beta gal. The many (from 1 to more than 20) ubiquitin moieties attached to a molecule of beta gal occur as an ordered chain of branched ubiquitin-ubiquitin conjugates in which the carboxyl-terminal Gly76 of one ubiquitin is jointed to the internal Lys48 of an adjacent ubiquitin. This multiubiquitin chain is linked to one of two specific Lys residues in beta gal. These same Lys residues have been identified by molecular genetic analysis as components of the aminoterminal degradation signal in beta gal. The experiments with ubiquitin mutated at its Lys48 residue indicate that the multiubiquitin chain in a targeted protein is essential for the degradation of the protein.

[1]  A. Varshavsky,et al.  The degradation signal in a short-lived protein , 1989, Cell.

[2]  A. Hershko.  Ubiquitin-mediated protein degradation. , 1988, The Journal of biological chemistry.

[3]  C. Pickart,et al.  Ubiquitin carrier protein-catalyzed ubiquitin transfer to histones. Mechanism and specificity. , 1988, The Journal of biological chemistry.

[4]  M. Goebl,et al.  The yeast cell cycle gene CDC34 encodes a ubiquitin-conjugating enzyme. , 1988, Science.

[5]  A. Hershko,et al.  A multicomponent system that degrades proteins conjugated to ubiquitin. Resolution of factors and evidence for ATP-dependent complex formation. , 1988, The Journal of biological chemistry.

[6]  R. E. Huber,et al.  The use of limited proteolysis to probe interdomain and active site regions of beta-galactosidase (Escherichia coli). , 1988, The Journal of biological chemistry.

[7]  B. Bullard,et al.  Arthrin, a myofibrillar protein of insect flight muscle, is an actin-ubiquitin conjugate , 1987, Cell.

[8]  D. Ecker,et al.  Gene synthesis, expression, structures, and functional activities of site-specific mutants of ubiquitin. , 1987, The Journal of biological chemistry.

[9]  L. Hood,et al.  Internal amino acid sequence analysis of proteins separated by one- or two-dimensional gel electrophoresis after in situ protease digestion on nitrocellulose. , 1987, Proceedings of the National Academy of Sciences of the United States of America.

[10]  Alexander Varshavsky,et al.  The yeast DNA repair gene RAD6 encodes a ubiquitin-conjugating enzyme , 1987, Nature.

[11]  C. Bugg,et al.  Comparison of the three-dimensional structures of human, yeast, and oat ubiquitin. , 1987, The Journal of biological chemistry.

[12]  C. Bugg,et al.  Structure of ubiquitin refined at 1.8 A resolution. , 1987, Journal of molecular biology.

[13]  A. Varshavsky,et al.  The yeast polyubiquitin gene is essential for resistance to high temperatures, starvation, and other stresses , 1987, Cell.

[14]  D. Ecker,et al.  Chemical synthesis and expression of a cassette adapted ubiquitin gene. , 1987, The Journal of biological chemistry.

[15]  A. Goldberg,et al.  Demonstration of two distinct high molecular weight proteases in rabbit reticulocytes, one of which degrades ubiquitin conjugates. , 1987, The Journal of biological chemistry.

[16]  A. Varshavsky,et al.  In vivo half-life of a protein is a function of its amino-terminal residue. , 1986, Science.

[17]  D. Finley,et al.  Enhancement of immunoblot sensitivity by heating of hydrated filters. , 1986, Analytical biochemistry.

[18]  K. Wilkinson,et al.  Tryptic peptide mapping of ubiquitin and derivatives using reverse-phase high performance liquid chromatography. , 1986, Analytical biochemistry.

[19]  T. Fujita,et al.  Functional receptors for vasoactive intestinal peptide in cultured vascular smooth muscle cells from rat aorta. , 1985, Biochemical and biophysical research communications.

[20]  A. Varshavsky,et al.  The ubiquitin system: functions and mechanisms , 1985 .

[21]  A. Hershko,et al.  Occurrence of a polyubiquitin structure in ubiquitin-protein conjugates. , 1985, Biochemical and biophysical research communications.

[22]  A. Ciechanover,et al.  Ubiquitin dependence of selective protein degradation demonstrated in the mammalian cell cycle mutant ts85 , 1984, Cell.

[23]  A. Ciechanover,et al.  Thermolability of ubiquitin-activating enzyme from the mammalian cell cycle mutant ts85 , 1984, Cell.

[24]  A Ciechanover,et al.  Proposed role of ATP in protein breakdown: conjugation of protein with multiple chains of the polypeptide of ATP-dependent proteolysis. , 1980, Proceedings of the National Academy of Sciences of the United States of America.

[25]  D. T. Brown,et al.  The functional repressor parts of a tetrameric lac repressor-beta-galactosidase chimaera are organized as dimers. , 1976, Proceedings of the National Academy of Sciences of the United States of America.

[26]  U. K. Laemmli,et al.  Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 , 1970, Nature.

[27]  K. Nagai,et al.  Synthesis and sequence-specific proteolysis of hybrid proteins produced in Escherichia coli. , 1987, Methods in enzymology.

[28]  P. Bornstein,et al.  [14] Cleavage at AsnGly bonds with hydroxylamine , 1977 .