High impact information on SIL1

• LHS1 and SIL1 provide a lumenal function that is essential for protein translocation into the endoplasmic reticulum [1].
• SIL1 is a non-essential gene but the Deltalhs1Deltasil1 double mutation is lethal and correlates with a complete block of protein translocation into the ER [1].
• We report on the identification of Fes1p (yBR101cp) as a cytosolic homologue of Sls1p, an endoplasmic reticulum (ER) protein previously shown to act as a nucleotide exchange factor for yeast BiP (M. Kabani, J.-M. Beckerich, and C. Gaillardin, Mol. Cell. Biol. 20:6923-6934, 2000) [2].
• Synthetic lethality was also observed with ER-associated degradation and folding-deficient kar2 mutants, strongly suggesting that Sls1p functions are not restricted to the translocation process [3].
• Moreover, Sls1p is shown to promote the Sec63p-mediated activation of Kar2p's ATPase activity [3].

Anatomical context of SIL1

• Sls1p was sedimented with membrane-rich organelles and was resistant to protease degradation without prior membrane solubilization [4].

Associations of SIL1 with chemical compounds

• The yeast FES1 and SLS1 genes encode conserved nucleotide exchange factors that act on the cytoplasmic and endoplasmic reticulum luminal Hsp70s, Ssa1p and BiP, respectively [5].
• We show that Sls1p stimulates in a dose-dependent manner the binding of ScKar2p on the lumenal J domain of Sec63p fused to glutathione S-transferase [3].

Other interactions of SIL1

• HspBP1, a homologue of the yeast Fes1 and Sls1 proteins, is an Hsc70 nucleotide exchange factor [5].
• Co-immunoprecipitation revealed that Sls1p resides close to the major translocation apparatus component, Sec61p [4].

Analytical, diagnostic and therapeutic context of SIL1

• A site-directed mutagenesis was performed on the SLS1 coding sequence that allowed us to define a functional domain in Sls1p [6].
• Indeed, we previously showed that the SLS1 gene product is involved in protein translocation across the endoplasmic reticulum membrane and interacts physically in a two-hybrid assay with Kar2p, an essential luminal member of the HSP70 family (Boisramé et al., 1998. J. Biol. Chem. 273, 30 903-30 908) [7].

References