Table 1 Factors involved in translocation of proteins across the ER membrane and their relationship to SLS
Factor | SRP54 | SRa | SEC61 | SEC63 | SEC71 |
|---|---|---|---|---|---|
Function | One of the SRP proteins recognizes the signal peptide | SRP receptor localized on the ER membrane | The translocon localized in the ER membrane | Factor essential for co- and post translational translocation | Factor essential exclusively for post-translation translocation |
Translocation defects in RNAi-silenced cells | Mislocalization of SP-proteins, no production of membrane proteins | Mislocalization of SP-proteins, no production of membrane proteins | Mislocalization of SP-proteins, no production of membrane proteins | Mislocalization of SP-proteins, no production of membrane proteins | Mislocalization of SP-proteins, reduction in GPI-anchored proteins, no effect on membrane proteins |
Induction of SLS | No | YES | YES | YES | NO |