1. Protein Transport Molecular Cell
Allison Robb, Jeremy D Brown 
Molecular Cell 
Volume 8, Issue 3, Pages (September 2001)
DOI: /S (01)

2. Figure 1 Translocation across the Yeast ER Membrane
The two pathways are depicted. In (A), the SRP-dependent cotranslational pathway (orange), a ribosome translating a protein with a hydrophobic signal sequence, is bound by SRP and becomes localized to the ER membrane through interaction with the SRP receptor (SR). The ribosome may be docked to either the Sec61p or Ssh1p translocon. In (B), the posttranslational pathway (blue), accepting proteins with less hydrophobic signal sequences (Ng et al., 1996), functions solely through Sec61p as only this translocon interacts with Sec62p. Recent evidence (Young et al., 2001) indicates that both pathways additionally require Sec63p and the ER lumenal hsp70 ortholog Kar2p (not depicted). The data of Wilkinson et al. (2001) suggest that the Sec61p translocon does not provide sufficient capacity to accommodate all proteins under maximum growth rates. Thus in the absence of Ssh1p, all SRP-targeted proteins are forced through Sec61p, leading to translocation defects for proteins that use either pathway. Both translocons function in dislocation (not shown)
Molecular Cell 2001 8, DOI: ( /S (01) )