同: coat protein II

同: coat protein II

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/07/23 17:22:23」(JST)

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For the 1996 United Nations Climate Change Conference in Geneva, Switzerland, see COP 2 (climate conference).

COPII is a type of vesicle coat protein that transports proteins from the rough endoplasmic reticulum to the Golgi apparatus.^[2]^[3] This process is termed anterograde transport, in contrast to the retrograde transport associated with the COPI protein. The name "COPII" refers to the specific coat protein complex that initiates the budding process. The coat consists of large protein subcomplexes that are made of four different protein subunits.

Coat proteins[edit]

There are two protein heterodimers that form the coat complex. These proteins are

Sec23p/Sec24p Heterodimer
Sec13p/Sec31p Heterotetramer

These proteins alone are not able to cause the budding of the vesicle or direct the vesicle to the correct target membrane. SNARE, cargo, and other proteins are also needed for these processes to occur. The CopII protein does, however, cause the binding that forms vesicle coat, and thereby causes the release from the ER. The exact process of how the vesicle is brought to a particular location, or how that location is determined is not yet known.

Budding process[edit]

The GTPase Sar1p is a protein that hydrolyzes GTP and acts like a molecular "switch" that flips between an activated and membrane embedded GTP-bound form, and inactive and soluble GDP-bound form. Inactive GDP-bound Sar1p is attracted to the cytosolic side of the endoplasmic reticulum (ER) membrane by Sec12p. Sec12p is a guanine nucleotide exchange factor, or GEF, and a transmembrane protein residing in the ER membrane. This binding event causes Sar1p to release GDP, and since the concentration of GTP is much higher than GDP in the cytosol, GTP spontaneously binds to Sar1p. Now in a GTP bound state, Sar1p undergoes a conformational change which exposes a hydrophobic tail that can be inserted into the lipid bilayer, binding it to the membrane. Once Sar1p is bound to the membrane the coat protein complexes Sec23p/24p and Sec13p/31p bind to the membrane sequentially. These proteins simultaneously contact Sar1p and cargo proteins destined for the cis-golgi membrane. The Sec23p/24p-Sec13p/31p-Sar1p complexes then coalesce to form a much larger complex. This network deforms the membrane enough to bud a vesicle off.

Conformational changes[edit]

CopII has three specific binding sites that can each be complexed. The picture on the right (Sed5) uses the Sec22 t-SNARE complex to bind. This site is more strongly bound, and therefore is more favored. (Embo)

Crystal structures of CopII

Conformation of the CopII protein complexed with the snare protein Bet1 (PDB 1PCX).^[4]

Conformation of the CopII protein that is complexed with the snare protein Sed5 (PDB 1PD0).^[4]

References[edit]

^ PDB 3EH1; Mancias JD, Goldberg J (November 2008). "Structural basis of cargo membrane protein discrimination by the human COPII coat machinery". EMBO J. 27 (21): 2918–28. doi:10.1038/emboj.2008.208. PMC 2580787. PMID 18843296.
^ Lee MC, Miller EA (August 2007). "Molecular mechanisms of COPII vesicle formation". Semin. Cell Dev. Biol. 18 (4): 424–34. doi:10.1016/j.semcdb.2007.06.007. PMID 17686639.
^ Hughes H, Stephens DJ (February 2008). "Assembly, organization, and function of the COPII coat". Histochem. Cell Biol. 129 (2): 129–51. doi:10.1007/s00418-007-0363-x. PMC 2228377. PMID 18060556.
^ ^a ^b 1PCX; 1PD0; Mossessova E, Bickford LC, Goldberg J (August 2003). "SNARE selectivity of the COPII coat". Cell 114 (4): 483–95. doi:10.1016/S0092-8674(03)00608-1. PMID 12941276.

English Journal

Molecular regulation of lysophosphatidic acid receptor 1 trafficking to the cell surface.

Zhao J1, Wei J1, Bowser RK1, Dong S2, Xiao S1, Zhao Y3.
Cellular signalling.Cell Signal.2014 Nov;26(11):2406-11. doi: 10.1016/j.cellsig.2014.07.005. Epub 2014 Jul 13.
The lysophosphatidic acid receptor 1 (LPA1), a G-protein coupled receptor, regulates cell proliferation, migration, and cytokine release. Here, we investigate the molecular signature of LPA1 trafficking to the cell surface. The overexpressed LPA1 with a C-terminal V5 tag (LPA1-V5) is majorly express
PMID 25025571

Absence of a Red Blood Cell Phenotype in Mice with Hematopoietic Deficiency of SEC23B.

Khoriaty R1, Vasievich MP2, Jones M3, Everett L2, Chase J3, Tao J4, Siemieniak D3, Zhang B4, Maillard I5, Ginsburg D6.
Molecular and cellular biology.Mol Cell Biol.2014 Oct 1;34(19):3721-34. doi: 10.1128/MCB.00287-14. Epub 2014 Jul 28.
Congenital dyserythropoietic anemia type II (CDAII) is an autosomal recessive disease of ineffective erythropoiesis characterized by increased bi/multinucleated erythroid precursors in the bone marrow. CDAII results from mutations in SEC23B. The SEC23 protein is a core component of coat protein comp
PMID 25071156

Concentration of Sec12 at ER exit sites via interaction with cTAGE5 is required for collagen export.

Saito K1, Yamashiro K2, Shimazu N2, Tanabe T2, Kontani K2, Katada T2.
The Journal of cell biology.J Cell Biol.2014 Sep 15;206(6):751-62. doi: 10.1083/jcb.201312062. Epub 2014 Sep 8.
Mechanisms for exporting variably sized cargo from the endoplasmic reticulum (ER) using the same machinery remain poorly understood. COPII-coated vesicles, which transport secretory proteins from the ER to the Golgi apparatus, are typically 60-90 nm in diameter. However, collagen, which forms a trim
PMID 25202031

Japanese Journal

細胞内小胞輸送でタンパク質を目的地へ：小胞体から始まる小胞輸送

膜 40(1), 2-8, 2015
NAID 130005069460

Traffic jam on the cellular secretory pathway generated by a replication protein from a plant RNA virus

Plant Signaling & Behavior 9(3), 2014-04-08
NAID 120005439155

CK2 Phosphorylates Sec31 and Regulates ER-To-Golgi Trafficking

PLoS ONE 8(1), 2013-01-18
NAID 120005311977

Related Pictures

★リンクテーブル★

拡張検索	「COPII-coated vesicle」「COPII被覆小胞」
関連記事	「COP」「COPI」

「COPII-coated vesicle」

SEC24 family, member A
Identifiers
Symbol	SEC24A
Entrez	10802
HUGO	10703
OMIM	607183
PDB	1M2V
RefSeq	XM_001132082
UniProt	O95486
Other data
Locus	Chr. 5 q31.1

Sec23 homolog A
	; Ribbon diagram of the crystallographic structure of the COPII heterodimer of Sec23 and Sec24. Alpha helices are in red and the beta sheets are in yellow.
Identifiers
Symbol	SEC23A
Entrez	856311
HUGO	10701
OMIM	610511
PDB	1M2V
RefSeq	NM_006364
UniProt	Q15436
Other data
Locus	Chr. 14 q21.1

　　[★]

コートタンパク質複合体II被覆小胞、COPII被覆小胞

関: coatomer-coated vesicle、COP-coated vesicle、COPI-coated vesicle

「COPII被覆小胞」

　　[★]

英: COPII-coated vesicle
関: コートタンパク質複合体II被覆小胞

「COP」

　　[★]

「COPI」

　　[★]

同: coat protein I

同: coat protein I

[pmid18843296-1] PDB 3EH1; Mancias JD, Goldberg J (November 2008). "Structural basis of cargo membrane protein discrimination by the human COPII coat machinery". EMBO J. 27 (21): 2918–28. doi:10.1038/emboj.2008.208. PMC 2580787. PMID 18843296.

[pmid17686639-2] Lee MC, Miller EA (August 2007). "Molecular mechanisms of COPII vesicle formation". Semin. Cell Dev. Biol. 18 (4): 424–34. doi:10.1016/j.semcdb.2007.06.007. PMID 17686639.

[pmid18060556-3] Hughes H, Stephens DJ (February 2008). "Assembly, organization, and function of the COPII coat". Histochem. Cell Biol. 129 (2): 129–51. doi:10.1007/s00418-007-0363-x. PMC 2228377. PMID 18060556.

[pmid12941276-4] 1PCX; 1PD0; Mossessova E, Bickford LC, Goldberg J (August 2003). "SNARE selectivity of the COPII coat". Cell 114 (4): 483–95. doi:10.1016/S0092-8674(03)00608-1. PMID 12941276.

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案内

案内

COPII