High impact information on SEC72

• Taken together, these results suggest a direct role for Sec63p, Sec71p, and Sec72p in nuclear membrane fusion and argue against the alternative interpretation that the karyogamy defects result as an indirect consequence of the impaired membrane translocation of another component(s) required for the process [1].
• Disruption of the genes encoding other Sec63p-associated proteins (Sec71p and Sec72p) also results in karyogamy defects [1].
• DNA sequence analysis of SEC72 predicts a 21.6-kD protein with neither a signal peptide nor any transmembrane domains [2].
• SEC72 is not essential for yeast cell growth, although an sec72 null mutant accumulates a subset of secretory precursors in vivo [2].
• We found that the ability of the p23 mutants to decrease or increase ER signal transduction correlated with their association with Hsp90 [3].

Biological context of SEC72

• 5. The sec72-1 mutation shifts the reading frame of the gene encoding p23 [4].
• We also identified a mutation in the C-terminal tail of p23, which displayed a dominant inhibitory effect on ER transcriptional activation and associates more avidly with Hsp90 relative to the wild type p23 [3].
• Interestingly, this mutant interacts with Hsp90 in its non-ATP-bound state, whereas the wild type p23 protein interacts exclusively with the ATP-bound form of Hsp90, which may account for its dominant phenotype [3].
• Deletion of the SBA1 gene (yeast p23 homolog) in this model system reduced ligand-mediated DR signaling by approximately 40% and shifted the EC(50) of the beta-napthoflavone ligand by five-fold in a reporter gene assay [5].

Associations of SEC72 with chemical compounds

• Genetic dissection of p23, an Hsp90 cochaperone, reveals a distinct surface involved in estrogen receptor signaling [3].
• In contrast, overexpression of p23 buffered the effects of radicicol and herbimycin A, but not novobiocin, on AhR signaling [6].

Other interactions of SEC72

• The Sec63p complex restores translocation activity to reconstituted vesicles that are prepared from a sec63-1 strain, or from cells in which the SEC66 or SEC67 genes are disrupted [7].
• The mutants were contained in three complementation groups, which we have named SEC70, SEC71, and SEC72 [8].

Analytical, diagnostic and therapeutic context of SEC72

• The map locations and precursor-product relationships of mature TYB1 polypeptides suggest that p23 is Ty1 protease, p90 is integrase, and p60 contains reverse transcriptase and RNase H. Immunoprecipitation and immunoblot analyses of Ty1 proteins show that p190 is cleaved to form p160 [9].

References