Exomer is a heterotetrameric
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...
complex similar to
COPI
COPI is a coatomer, a protein complex that coats vesicles transporting proteins from the ''cis'' end of the Golgi complex back to the rough endoplasmic reticulum (ER), where they were originally synthesized, and between Golgi compartments. This ...
and other
adaptins.
It was first described in the
yeast
Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to consti ...
''
Saccharomyces cerevisiae
''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have been o ...
''.
Exomer is a cargo adaptor important in transporting molecules from the
Golgi apparatus
The Golgi apparatus (), also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. Part of the endomembrane system in the cytoplasm, it packages proteins into membrane-bound vesicles ...
toward the
cell membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (the ...
. The vesicles it is found on are different from COPI vesicles in that they do not appear to have a "coat" or "scaffold" around them.
[
An overview of the cellular localization of exomer and other cargo adaptor]
is shown here
Exomer binds to
2 molecules of ADP-ribosylation factor 1 (Arf1) as show
in this figure
A hinge region of exomer is thought to be important for forming to a highly curved membrane vesicle[ as show]
in this figure
The steps of assembly of exomer on a Golgi membrane are show
in this figure
See also
*AP2 adaptor complex The AP2 adaptor complex is a multimeric protein that works on the cell membrane to internalize cargo in clathrin-mediated endocytosis. It is a stable complex of four adaptins which give rise to a structure that has a core domain and two appendage ...
*Clathrin
Clathrin is a protein that plays a major role in the formation of coated vesicles. Clathrin was first isolated and named by Barbara Pearse in 1976. It forms a triskelion shape composed of three clathrin heavy chains and three light chains. Wh ...
vesicles
*COPII
The Coat Protein Complex II, or COPII, is a group of proteins that facilitate the formation of vesicles to transport proteins from the endoplasmic reticulum to the Golgi apparatus or endoplasmic-reticulum–Golgi intermediate compartment. This pr ...
vesicles
References
{{reflist, 2
Protein complexes