SPC2/YML055W Summary Help

Standard Name SPC2 1
Systematic Name YML055W
Alias SPY1
Feature Type ORF, Verified
Description Subunit of signal peptidase complex; complex catalyzes cleavage of N-terminal signal sequences of proteins targeted to the secretory pathway; homologous to mammalian SPC25; other members of the complex are Spc1p, Spc1p, and Sec11p (1, 2, 3, 4 and see Summary Paragraph)
Name Description Signal Peptidase Complex 1
Chromosomal Location
ChrXIII:164790 to 165326 | ORF Map | GBrowse
Gene Ontology Annotations All SPC2 GO evidence and references
  View Computational GO annotations for SPC2
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Classical genetics
Large-scale survey
153 total interaction(s) for 75 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 5
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 3
  • Co-purification: 1
  • PCA: 7
  • Two-hybrid: 6

Genetic Interactions
  • Negative Genetic: 74
  • Phenotypic Enhancement: 10
  • Phenotypic Suppression: 33
  • Positive Genetic: 6
  • Synthetic Growth Defect: 3
  • Synthetic Lethality: 3

Expression Summary
Length (a.a.) 178
Molecular Weight (Da) 20,802
Isoelectric Point (pI) 10.07
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXIII:164790 to 165326 | ORF Map | GBrowse
Last Update Coordinates: 1996-07-31 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..537 164790..165326 1996-07-31 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000004519

SPC2 encodes a subunit of the signal peptidase complex (SPC), which cleaves the signal sequence from proteins targeted to the endoplasmic reticulum (ER) (1). Signal peptide cleavage occurs concomitantly with translocation through the translocon pore into the ER. In yeast, translocation can occur cotranslationally or posttranslationally, whereas in mammals translocation is always cotranslational. The process of protein translocation into the ER is reviewed in references 5 and 6.

The yeast SPC comprises four proteins, Spc1p, Spc2p, Spc3p, and Sec11p (7, 4). Spc2p is homologous to the mammalian signal peptidase subunit SPC25 (1). Spc2p is not essential for viability or for signal peptidase activity (1, 4), but deletion of SPC2 reduces signal peptidase activity in vitro (4). The spc2 null mutant also shows reduced levels of the other SPC subunits (4), and is synthetically lethal with a temperature-sensitive mutation in SEC11 (1).

Spc2p can be coimmunoprecipitated with Sbh1p and Sbh2p, which are beta subunits of two different "Sec61" complexes involved in ER membrane translocation (4, 6). The genetic and physical interactions observed suggest that Spc2p may facilitate interactions between different components of the translocation machinery (4).

Last updated: 2000-11-28 Contact SGD

References cited on this page View Complete Literature Guide for SPC2
1) Mullins C, et al.  (1996) Structurally related Spc1p and Spc2p of yeast signal peptidase complex are functionally distinct. J Biol Chem 271(46):29094-9
2) Fang H, et al.  (1997) In addition to SEC11, a newly identified gene, SPC3, is essential for signal peptidase activity in the yeast endoplasmic reticulum. J Biol Chem 272(20):13152-8
3) Meyer HA and Hartmann E  (1997) The yeast SPC22/23 homolog Spc3p is essential for signal peptidase activity. J Biol Chem 272(20):13159-64
4) Antonin W, et al.  (2000) Interactions between Spc2p and other components of the endoplasmic reticulum translocation sites of the yeast Saccharomyces cerevisiae. J Biol Chem 275(44):34068-72
5) Rapoport TA, et al.  (1996) Protein transport across the eukaryotic endoplasmic reticulum and bacterial inner membranes. Annu Rev Biochem 65:271-303
6) Johnson AE and van Waes MA  (1999) The translocon: a dynamic gateway at the ER membrane. Annu Rev Cell Dev Biol 15:799-842
7) YaDeau JT, et al.  (1991) Yeast signal peptidase contains a glycoprotein and the Sec11 gene product. Proc Natl Acad Sci U S A 88(2):517-21