| Title: | Degradation signal masking by heterodimerization of MATalpha2 and MATa1 blocks their mutual destruction by the ubiquitin-proteasome pathway |
| Author(s): | Johnson PR; Swanson R; Rakhilina L; Hochstrasser M; |
| Address: | "Department of Biochemistry and Molecular Biology, University of Chicago, Illinois 60637, USA" |
| DOI: | 10.1016/s0092-8674(00)81421-x |
| ISSN/ISBN: | 0092-8674 (Print) 0092-8674 (Linking) |
| Abstract: | "Proteolysis by the ubiquitin-proteasome pathway is often regulated, but the mechanisms underlying such regulation remain ill-defined. In Saccharomyces cerevisiae, cell type is controlled by the MAT transcription factors. The alpha2 repressor is a known ubiquitin pathway substrate in alpha haploid cells. We show that a1 is rapidly degraded in a haploids. In a/alpha diploids, alpha2 and a1 are stabilized by heterodimerization. Association depends on N-terminal coiled-coil interactions between a1 and alpha2. Residues in alpha2 important for these interactions overlap a critical determinant of an alpha2 degradation signal, which we delimit by extensive mutagenesis. Our data provide a detailed description of a natural ubiquitin-dependent degradation signal and point to a molecular mechanism for regulated turnover in which proteolytic signals are differentially masked in alternative multiprotein complexes" |
| Keywords: | Amino Acid Sequence Cysteine Endopeptidases/*metabolism Dimerization Diploidy Fungal Proteins/chemistry/genetics Haploidy Intramolecular Transferases Lipoproteins/chemistry/*metabolism Mating Factor Molecular Sequence Data Multienzyme Complexes/*metabolis; |
| Notes: | "MedlineJohnson, P R Swanson, R Rakhilina, L Hochstrasser, M eng GM07183/GM/NIGMS NIH HHS/ GM46904/GM/NIGMS NIH HHS/ Research Support, U.S. Gov't, P.H.S. 1998/08/08 Cell. 1998 Jul 24; 94(2):217-27. doi: 10.1016/s0092-8674(00)81421-x" |
