COPII-coated vesicles: flexible enough for large cargo?
Cargo proteins exiting the endoplasmic reticulum en route to the Golgi are typically carried in 60-70 nm vesicles surrounded by the COPII protein coat. Some secretory cargo assemblies in specialized mammalian cells are too large for transport within such carriers. Recent studies on procollagen-I and chylomicron trafficking have reached conflicting conclusions regarding the role of COPII proteins in ER exit of these large biological assemblies. COPII is no doubt essential for such transport in vivo, but it remains unclear whether COPII envelops the membrane surrounding large cargo or instead plays a more indirect role in transport carrier biogenesis.
Department of Molecular and Cell Biology, University of California-Berkeley, 628 Barker Hall #3202, Berkeley, CA 94720-3202, USA.
J Christopher
JC
Fromme
Randy
R
Schekman
D000818:Animals; D001692:Biological Transport; D022181:COP-Coated Vesicles / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D024022:Fibrillar Collagens / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D008074:Lipoproteins / Q000378:metabolism
D024022:Fibrillar Collagens; D008074:Lipoproteins