Cisterna

A cisterna (plural cisternae) is a flattened membrane disk of the endoplasmic reticulum and Golgi apparatus. A Golgi stack may contain anywhere from three to twenty cisternae, but most contain about six cisternae. Golgi cisternae can be separated into four classes; cis, medial, trans, and TGN (trans-Golgi network).[1] Each cisternae class contain different enzymes working within it. This helps to prevent any redundant enzymatic activity.[1] Almost all cisternae in the Golgi apparatus present multiple stacking. There are only eight instances in which the stacked characteristic has been lost.[2]

Function

Cisternae pack and modify proteins and polysaccharides. Biosynthetic cargo proteins travel through cisternae and undergo glycan remodeling and other modifications. Cisternae package the proteins and then send them to transport carriers. They also package polysaccharides that are synthesized in the Golgi apparatus. The compounds enter at the cis face of the Golgi stack and exit out the trans side where most of the packaging occurs.[1]

The functions of cisternae change as it undergoes micromaturation. Immature cisternae receive COPII vesicles from the endoplasmic reticulum.[3] During this stage, new cisternae can be produced. The next stage begins when cisternae at carbohydrate synthesis swap material via COPI vesicles. This is when glycosylation and polysaccharide synthesis occur. Mature cisternae reach the final stage where cargo proteins are sent to transport carriers and finally the cisternae disassemble.[1]

References

  1. 1 2 3 4 Day, Kasey J.; Staehelin, L. Andrew; Glick, Benjamin S. (2013-07-24). "A three-stage model of Golgi structure and function". Histochemistry and Cell Biology. 140 (3): 239–249. doi:10.1007/s00418-013-1128-3. ISSN 0948-6143. PMC 3779436. PMID 23881164.
  2. ↑ Klute, Mary J.; Melançon, Paul; Dacks, Joel B. (2011-08-01). "Evolution and Diversity of the Golgi". Cold Spring Harbor Perspectives in Biology. 3 (8): a007849. doi:10.1101/cshperspect.a007849. ISSN 1943-0264. PMC 3140683. PMID 21646379.
  3. ↑ Bankaitis, Vytas A.; Garcia-Mata, Rafael; Mousley, Carl J. "Golgi Membrane Dynamics and Lipid Metabolism". Current Biology. 22 (10): R414–R424. doi:10.1016/j.cub.2012.03.004. ISSN 0960-9822. PMC 4059015. PMID 22625862.


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