| Summary: | 碩士 === 國立臺灣大學 === 微生物學研究所 === 106 === We have previously found a protein, Ids2 (IME2-dependent signaling protein), de-phosphorylated under CR, and loss of Ids2 leads to CLS extension, mitochondrial defects, and heat intolerant phenotype. The analysis of tandem affinity purification of Ids2 revealed its interaction with Hsp90, including Hsc82 and Hsp82 in yeast. Heat shock protein 90 (HSP90) is a highly conserved molecular chaperone in eukaryotes, which is necessary for folding, maturation, and activity of numerous client proteins. Thus, it plays an essential role in many physiological processes such as signal transduction and cell proliferation. Such chaperone function requires a large group of helper proteins, termed co-chaperones, which participate in the various conformational state of the HSP90 chaperone cycle and regulate its activity. Previous evidence indicated that Ids2 may serve as a co-chaperone of HSP90 and its phosphorylation at residue 148 may affect the interaction between Ids2 and HSP90. However, the molecular mechanism remains elusive. I therefore screened interacting partners of Ids2, hoping to discover potential clients whose protein folding is dependent on the Ids2-HSP90 complex. S-adenosylmethionine synthase 1 (Sam1) was found that both the protein expression and enzymatic function of Sam1 decreased in ids2∆ strains. The further evidence showed that deletion of IDS2 led to foci formation of Sam1; nevertheless, interestingly, ids2 phosphor-mimicking mutation did not influence the protein expression of TAP-tagged Sam1 but did damage the function of it. Besides, the physical interaction was confirmed between Ids2, Hsc82, and Sam1. Together, Ids2 may function as a co-chaperone to affect the activity of the Ids2-Hsc82-Sam1 complex.
|
|---|
