- 同
- exocytotic
WordNet
- a trodden path (同)footpath
- of or relating to or producing a secretion; " a secretory cell"
PrepTutorEJDIC
- 道,小道(path)
Wikipedia preview
出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2014/04/09 12:52:49」(JST)
[Wiki en表示]
The secretory pathway is a series of steps a cell uses to move proteins out of the cell; a process known as secretion. The path of a protein destined for secretion has its origins in the rough endoplasmic reticulum, a membrane-bound compartment in the cell. The protein then proceeds through the many compartments of the Golgi apparatus and finally ends up in a vesicle that transiently fuses at the cell plasma membrane via permanent plasma membrane structures called porosomes, depositing the proteins outside of the cell.
At each step along the way there are crucial factors that determine how and if the protein will proceed. Some of these factors include regulation of transportation, selection of particular proteins, the mechanics of proceeding to the next step, and modifications that can occur to the protein along the way. All of these factors contribute to how a protein arrives outside of a cell after being synthesized.
Contents
- 1 General regulation
- 2 Protein translocation
- 3 See also
- 4 References
General regulation
In general, there are two different patterns of secretion. One pattern is called constitutive secretion. Proteins are continuously secreted from the cell regardless of environmental factors. No external signals are needed to initiate this process. Proteins are packaged in vesicles in the Golgi apparatus and are secreted via exocytosis, all around the cell. Cells that secrete constitutively have Golgi apparatus scattered throughout the cytoplasm. Fibroblasts, osteoblasts and chondrocytes are some of the many cells that perform constitutive secretion.
In regulated secretion, proteins are packaged as described in the constitutive pathway, but they are only secreted in response to a specific signal, such as neural or hormonal stimulation. Cells that use the regulated secretory pathway are usually apical or polarized. The Golgi apparatus is found in a supranuclear position (between the nucleus and the secretory surface). Examples of cells that use regulated pathway are: goblet cells (secrete mucus), beta cells of the pancreas (secrete insulin) and odontoblasts (secrete dentin). The protein pathway consists of eight steps total.
Protein translocation
The first step in a protein's journey out of the cell is getting into the endoplasmic reticulum. Two methods exist for proteins to accomplish this.
- Co-translational translocation is the action of a protein being fed into the ER as it is synthesized by the ribosome. In this scenario the protein begins to be translated normally. As the N-terminus (the first end of the protein to be synthesized) leaves the ribosome, a short sequence of the nascent protein's amino acids is recognized by a protein complex called SRP, or signal recognition particle. SRP binds to this sequence of amino acids and then subsequently binds to a protein complex called the SRP receptor embedded in the ER membrane. Both the SRP complex and SRP receptor complex hydrolyze a molecule of GTP into GDP. Once this occurs the growing protein chain is moved to a membrane channel called the translocon. It is through this hole in the ER membrane that the protein passes through as it is synthesized. The result of all this is a new protein residing within the membrane of the endoplasmic reticulum.
- Post-translational translocation is the action of a protein passing into the ER following synthesis by the ribosome.
Recently, protein translocation from prokaryotic gram negative microbes contained in bacterial outer membrane bounded vesicles has come to light. Fully conformed globular proteins of microbial origin can be translocated into eukaroytic host cells or targeted to other microbes in the micro-environment.[1]
See also
- Secretion
- Signal peptide
- Protein targeting
- SecY protein
References
- Lodish, Harvey, et al. (2003) Molecular Cell Biology 5th Edition. W. H. Freeman
- ^ YashRoy R.C. (1999) 'Exocytosis in prokaryotes' and its role in Salmonella invasion. ICAR NEWS, vol. 5(No.4), page 18. https://www.researchgate.net/publication/230822402_'Exocytosis_in_prokaryotes'_and_its_role_in_Salmonella_invasion?ev=prf_pub
UpToDate Contents
全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.
English Journal
- New insights into the Ca(2+)-ATPases that contribute to cadmium tolerance in yeast.
- Mielniczki-Pereira AA, Hahn AB, Bonatto D, Riger CJ, Eleutherio EC, Henriques JA.SourceUniversidade Integrada do Alto Uruguai e das Missoes (URI), Av. Sete de Setembro 1621, Cep 99700-000 Erechim, RS, Brazil.
- Toxicology letters.Toxicol Lett.2011 Nov 30;207(2):104-11. Epub 2011 Sep 3.
- Cadmium (Cd(2+)) is a toxic heavy metal which triggers several toxic effects in eukaryotes, including neurotoxicity and impaired calcium metabolism. In the model organism Saccharomyces cerevisiae, the best characterized pathway for Cd(2+) detoxification involves conjugation with glutathione (GSH) an
- PMID 21911041
- N-Glycan synthesis in the apical and basolateral secretory pathway of epithelial MDCK cells and the influence of a glycosaminoglycan domain.
- Moen A, Hafte TT, Tveit H, Egge-Jacobsen W, Prydz K.SourceDepartment of Molecular Biosciences, University of Oslo, Box 1041, Blindern, 0316 Oslo, Norway.
- Glycobiology.Glycobiology.2011 Nov;21(11):1416-25. Epub 2011 Jun 14.
- Different classes of glycans are implicated as mediators of apical protein sorting in the secretory pathway of epithelial cells, but recent research indicates that sorting to the apical and basolateral surfaces may occur before completion of glycan synthesis. We have previously shown that a proteogl
- PMID 21673010
Japanese Journal
- 酵母分泌経路におけるRab-GEFカスケードの調節
- GABA accumulation causes cell elongation defects and a decrease in expression of genes encoding secreted and cell wall-related proteins in Arabidopsis thaliana
- Renault Hugues,Amrani Abdelhak El,Palanivelu Ravishankar [他]
- Plant and Cell Physiology 52(5), 894-908, 2011-05
- NAID 40018810240
Related Links
- From Wikipedia, the free encyclopedia. Jump to: navigation, search. The secretory pathway is a series of steps a cell uses to move proteins out of the cell; a process known as secretion. The path of a protein destined for secretion has its origins ...
★リンクテーブル★
[★]
- 英
- [[]]
- 同
- secretory pathway
- 関
- [[]]
- 同
- secretory pathway
[★]
- 関
- route
[★]