High impact information on SPC3

• Genetic and biochemical experiments demonstrate that Sec11p and Spc3p are tightly associated with two other proteins, Spc1p and Spc2p, whose functions are largely unknown [1].
• In yeast, the endoplasmic reticulum membrane proteins Sec11p and Spc3p are essential for the cleavage of signal peptides of nascent polypeptide chains during their passage through translocation sites [1].
• In addition to SEC11, a newly identified gene, SPC3, is essential for signal peptidase activity in the yeast endoplasmic reticulum [2].
• We find that Spc3p is also required for cell growth and signal peptidase activity within the yeast endoplasmic reticulum [2].
• The heterologous complementation of the sec61 mutant suggests that Spc3p could play a role in the interaction that it is known to occur between the translocon (Sec61 complex) and the signal peptidase complex, at the endoplasmic reticulum membrane [3].

Biological context of SPC3

• The cloned gene could rescue the phenotype associated with a spc3 mutation in S. cerevisiae, indicating that it is the true C. albicans orthologue of SPC3 [3].
• Depletion of Spc2p decreased the enzymatic activity of the SPC in vitro, led to a loss of Spc1p, and led to a down-regulation of the amount of Sec11p and Spc3p in the endoplasmic reticulum [1].

Anatomical context of SPC3

• In the hypothalamus overlapping and unique distributions of the two transcripts were seen in the paraventricular nucleus with SPC3 mRNA predominantly expressed in lateral magnocellular cells [4].
• SPC3 mRNA was most abundant in dentate gyrus granule cells, the habenula and selected hypothalamic nuclei [4].
• SPC3 mRNA, but not SPC2 transcripts, also colocalized with immunoreactive vasopressin-associated neurophysin in the suprachiasmatic nucleus [4].
• Combined immunocytochemistry/in situ hybridization histochemistry demonstrated that SPC2 and SPC3 transcripts were both expressed in the vasopressinergic subpopulation of magnocellular neurons in the supraoptic nucleus [4].

Other interactions of SPC3

• The Candida albicans orthologue of the SPC3 gene, which encodes one of the subunits essential for the activity of the signal peptidase complex in Saccharomyces cerevisiae, was isolated by complementation of a thermosensitive mutation in the S. cerevisiae SEC61 gene [3].

References