Vesicles and Complexes

• Mediate first leg of the biosynthetic pathway
• Select and concentrate certain components for transport as long as they have an ER export signal as part of their cytosolic tail
• -          Binds proteins that will function in later stages in the pathway, help docking and fusion, or can bind soluble particles

Contains a small Gprotein called Sar1, which plays a regulatory role by initiating vesicle formation and regulating the assembly of the vesicle coat

• Function in the retrograde transport of proteins , such as transà cis or ERGIC à ER
• -          retaining or retrieval

• Contains a membrane bending protein called Arf1

Contains receptors that recognize and bind mitochondrial proteins and protein-lined channels through which unfolded polypeptides are translocated across the outer membrane

OMM

IMM

Binds integral proteins of the IMM that contain an internal targeting sequence and inserts them into the lipid bilayer

Binds proteins with an N-terminal presequence, which includes all of the proteins of the matrix; it recognizes and translocates the matrix proteins completely through the IMM and into the inner aqueous compartment