TABLE 7.
Components of Sec-dependent protein export machineries of B. subtilis, E. coli, M. jannaschii, and the ER of S. cerevisiaea
| Component | B. subtilis | E. coli | M. jannaschii | S. cerevisiae |
|---|---|---|---|---|
| Secretion-dedicated chaperones | Ffh, FtsY, scRNA | Ffh, FtsY, 4.5S RNA | Srp54/19, FtsY, 7S RNA | SRP complex,b DPα/β |
| SecB | ||||
| CsaA (?) | YgjH (?) | |||
| General chaperones | GroEL, GroES | GroEL, GroES | ||
| DnaK, DnaJ, GrpE | DnaK, DnaJ, GrpE | Hsp70, Ydj1 | ||
| Trigger factor | Trigger factor | |||
| Translocation motor | SecA | SecA | ||
| Ribosome | ||||
| Kar2 (Bipc) | ||||
| Translocation channel | SecY | SecY | SecY | Sec61, Ssh1 (Sec61αc) |
| SecG | SecG | Sec61β | Sbh1, Sbh2 (Sec61βc) | |
| SecE | SecE | SecE | Sss1 (Sec61γc) | |
| SecDF, YrbF | SecD/F, YajC | SecD/F | ||
| Sec62/63 | ||||
| Sec66/67 | ||||
| SPases | SipS/T/U/V/P | LepB | ||
| SipW | Sec11 | Sec11 | ||
| LspA | LspA | |||
| SPPases | SppA | SppA | SppA | |
| TepA | ||||
| OpdA | ||||
| Foldases (trans-acting) | PrsA | SurA, PpiD, RotA, FkpA | CPR2, CPR4, CPR5, CPR8, FPR2 | |
| BdbA/B/C | DsbA/B/C/D/E/G | PDI, Ero1, Eug1 | ||
| Kar2 (BiPc), Lhs1 (Hsp70c) |
a
Proteins with similar functions are placed in the same horizontal row.
b
The SRP complex consists of scR1 RNA, Srp72p, Srp68p, Srp54p, Sec65p, Srp21p, Srp14p, and Srp7p (338).
c
Synonymous names for mammalian homologues.