SGT2 and MDY2 interact with molecular chaperone YDJ1 in Saccharomyces cerevisiae.
In Saccharomyces cerevisiae, Sgt2 was thought to be the homologue of vertebrate SGT (small glutamine tetratricopeptide repeat-containing protein). SGT has been known to interact with both Hsp70 and Hsp90. However, it was not clear whether Sgt2 might have a similar capacity. Here, we showed that Ssa1/Ssa2 (yeast heat shock cognate [Hsc]70), Hsc82 (yeast Hsp90), and Hsp104 coprecipitated with Sgt2 from yeast lysates. Another molecular chaperone, Ydj1, known to interact with Ssal and Hsc82, also coprecipitated with Sgt2. Synthetic lethality between SGT2 and YDJ1 was observed after the cells were under stress, although Sgt2 might not interact physically with Ydj1. We also found that Mdy2 interacted with the N-terminal region of Sgt2 and that Mdy2 appeared to interact physically with Ydj1. Mdy2 therefore may mediate the association of Ydj1 and Sgt2. In addition, the mating efficiency of mdy2delta, sgt2delta, and mdy2deltasgt2delta strains was reduced to a similar extent. Compared with mdy2delta and ydj1delta cells, ydj1deltamdy2delta cells, however, showed a further suppression in mating efficiency. Moreover, MDY2 interacted genetically with YDJ1. These results suggest that protein complexes containing Sgt2 and Mdy2 bring molecular chaperones together to carry out certain chaperoning functions.
Liou
Shen-Ting
ST
Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
Cheng
Ming-Yuan
MY
Wang
Chung
C
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D047468:Immunoprecipitation; D018832:Molecular Chaperones / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; D050956:HSP40 Heat-Shock Proteins; C510068:Mdy2 protein, S cerevisiae; D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins; C520576:Sgt2 protein, S cerevisiae; D025801:Ubiquitin; C070319:YDJ1 protein, S cerevisiae