A Primer on Vesicle Budding
نویسندگان
چکیده
How do vesicular coats form on the donor membrane? Sebastian Springer,* Anne Spang,* and Randy Schekman*†‡ Do cargo proteins influence this process? Recent work *Department of Molecular and Cell Biology and on the exchange of proteins between the endoplasmic †Howard Hughes Medical Institute reticulum (ER) and the Golgi apparatus in SaccharoUniversity of California myces cerevisiae and higher eukaryotes suggests that Berkeley, California 94720 all three requirements for functional vesicle budding could be regulated in a single mechanistic step, the formation of a “priming complex” of a small GTPase, a Transport vesicles carry lumenal and membrane cargo membrane protein, and a coat subunit (Figure 1). proteins between secretory organelles in eukaryotic To Begin: Recruit a GTPase cells. To make such a vesicle, cytosolic coat proteins to the Donor Membrane assemble on a donor membrane and deform it into a COPII (coat protein complex II)–coated vesicles transbud. Cargo proteins are sorted into the originating vesiport proteins from the ER to the Golgi. The COPII coat cle, which then separates from the donor membrane, consists of the small GTPase Sar1p and the heteroditravels a certain distance, and finally fuses with the acmeric protein complexes Sec23/24p and Sec13/31p ceptor organelle. (Barlowe, 1998). These five proteins are necessary and At the time of vesicle budding, three specific requiresufficient to produce COPII vesicles from ER microments have to be fulfilled in order to produce a functional somes (Barlowe et al., 1994) and from chemically defined vesicle. First, different vesicular transport processes are liposomes (Matsuoka et al., 1998). mediated by different coat protein complexes, and Proteins can also be recycled to the ER from the cistherefore a donor membrane must attract the correct Golgi via a backward, or retrograde, route. Such proteins species of cytosolic coat proteins. Second, a transport include ER residents that have escaped ER retention, vesicle needs to be equipped with certain membrane and functional components of COPII (“anterograde”) proteins that have essential tasks at a later stage. vesicles that return to participate in another round of v-SNAREs, for example, are required for fusion with the COPII vesicle formation. Retrograde vesicles are coated acceptor membrane (reviewed by Nichols and Pelham, with the COPI coat (Cosson and Letourneur, 1997; 1998). These proteins must be included into the vesicles Gaynor et al., 1998), which consists of the small GTPase with high fidelity. And third, cargo proteins have to be recognized and included into the originating vesicles. ARF (in S. cerevisiae, Arf1p and/or Arf2p) and coatomer
منابع مشابه
The yeast p24 complex is required for the formation of COPI retrograde transport vesicles from the Golgi apparatus
The p24 family members are transmembrane proteins assembled into heteromeric complexes that continuously cycle between the ER and the Golgi apparatus. These cargo proteins were assumed to play a structural role in COPI budding because of their major presence in mammalian COPI vesicles. However, this putative function has not been proved conclusively so far. Furthermore, deletion of all eight ye...
متن کاملALG-2 Attenuates COPII Budding In Vitro and Stabilizes the Sec23/Sec31A Complex
Coated vesicles mediate the traffic of secretory and membrane cargo proteins from the endoplasmic reticulum (ER) to the Golgi apparatus. The coat protein complex (COPII) involved in vesicle budding is constituted by a GTPase, Sar1, the inner coat components of Sec23/Sec24 and the components of the outer coat Sec13/Sec31A. The Ca(2+)-binding protein ALG-2 was recently identified as a Sec31A bind...
متن کاملVesicular transport: the core machinery of COPI recruitment and budding.
Vesicular transport is the predominant mechanism for exchange of proteins and lipids between membrane-bound organelles in eukaryotic cells. Golgi-derived COPI-coated vesicles are involved in several vesicular transport steps, including bidirectional transport within the Golgi and recycling to the ER. Recent work has shed light on the mechanism of COPI vesicle biogenesis, in particular the machi...
متن کاملThe synaptic vesicle cycle: a single vesicle budding step involving clathrin and dynamin
Strong evidence implicates clathrin-coated vesicles and endosome-like vacuoles in the reformation of synaptic vesicles after exocytosis, and it is generally assumed that these vacuoles represent a traffic station downstream from clathrin-coated vesicles. To gain insight into the mechanisms of synaptic vesicle budding from endosome-like intermediates, lysed nerve terminals and nerve terminal mem...
متن کاملWetting-Induced Budding of Vesicles in Contact with Several Aqueous Phases
Osmotic deflation of vesicles enclosing two liquid phases can lead to bulging of one of the phases from the vesicle body. This budding process is preceded by a complete to partial wetting transition of one of the liquid phases on the membrane and depends on the membrane tensions and the tension of the interface between the enclosed liquid phases. These tensions dominate in different morphology ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Cell
دوره 97 شماره
صفحات -
تاریخ انتشار 1999