Lysosome

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Cell biology
The ainimal cell
Animal Cell.svg
Components o a teepical ainimal cell:
  1. Nucleolus
  2. Nucleus
  3. Ribosome (little dots)
  4. Vesicle
  5. Rough endoplasmic reticulum
  6. Golgi apparatus (or "Golgi body")
  7. Cytoskeleton
  8. Smuith endoplasmic reticulum
  9. Mitochondrion
  10. Vacuole
  11. Cytosol (fluid that contains organelles)
  12. Lysosome
  13. Centrosome
  14. Cell membrane

A lysosome (derived frae the Greek wirds lysis, meanin "tae loosen", an soma, "body") is a membrane-boond cell organelle foond in maist ainimal cells (thay are absent in reid bluid cells). Thay are spherical vesicles that conteen hydrolytic enzymes that can brak doun mony kynds o biomolecules. A lysosome haes a speceefic composeetion, o baith its membrane proteins, an its lumenal proteins. The lumen's pH (4.5–5.0)[1] is optimal for the enzymes involved in hydrolysis, analogous tae the activity o the stomach. Asides degradation o polymers, the lysosome is involved in various cell processes, includin secretion, plasma membrane repair, cell srrgnalin, an energy metabolism.[2]

The lysosomes an aw act as the waste disposal seestem o the cell bi digeestin unwantit materials in the cytoplasm, baith frae ootside the cell an obsolete components inside the cell. Material frae ootside the cell is taken-up throu endocytosis, while material frae the inside o the cell is digeestit throu autophagy. Thair sizes can be verra different—the lairgest anes can be mair nor 10 times the size o the smawest anes.[3] Thay war diskivert an named bi Belgian biologist Christian de Duve, that eventually received the Nobel Prize in Pheesiology or Medicine in 1974.

Lysosomes are kent tae conteen mair nor 60 different enzymes.[4][5] Enzymes o the lysosomes are synthesised in the roch endoplasmic reticulum. The enzymes are importit frae the Golgi apparatus in smaw vesicles, that fuse wi lairger acidic vesicles. Enzymes destined for a lysosome are speceefically tagged wi the molecule mannose 6-phosphate, sae that thay are properly sortit intae acidifee'd vesicles.[6][7]

Synthesis o lysosomal enzymes is controlled bi nuclear genes. Mutations in the genes for thir enzymes are responsible for mair nor 30 different human genetic disorders, that are collectively kent as lysosomal storage diseases. Thir diseases result frae an accumulation o speceefic substrates, due tae the inability tae break them doun. Thir genetic defects are relatit tae several neurodegenerative disorders, cancers, cardiovascular diseases, an agein-relatit diseases.[8][9]

Lysosomes shoud nae be confused wi liposomes, or wi micelles.

References[eedit | eedit soorce]

  1. Mindell JA (2012). "Lysosomal Acidification Mechanisms". Annual Review of Physiology. 74 (1): 69–86. doi:10.1146/annurev-physiol-012110-142317. PMID 22335796. 
  2. Settembre C, Fraldi A, Medina DL, Ballabio A (May 2013). "Signals from the lysosome: a control centre for cellular clearance and energy metabolism". Nature Reviews Molecular Cell Biology. 14 (5): 283–96. doi:10.1038/nrm3565. PMC 4387238Freely accessible. PMID 23609508. 
  3. Lüllmznn-Rauch R (2005). "History and Morphology of Lysosome". In Zaftig P. Lysosomes (Online-Ausg. 1 ed.). Georgetown, Tex.: Landes Bioscience/Eurekah.com. pp. 1–16. ISBN 978-0-387-28957-1. 
  4. Xu, Haoxing; Ren, Dejian (2015). "Lysosomal physiology". Annual Review of Physiology. 77 (1): 57–80. doi:10.1146/annurev-physiol-021014-071649. PMC 4524569Freely accessible. PMID 25668017. 
  5. "Lysosomal Enzymes". www.rndsystems.com. R&D Systems. Retrieved 4 October 2016. 
  6. Saftig, Paul; Klumperman, Judith (2009). "Lysosome biogenesis and lysosomal membrane proteins: trafficking meets function". Nature Reviews Molecular Cell Biology. 10 (9): 623–635. doi:10.1038/nrm2745. PMID 19672277. 
  7. Samie, M. A.; Xu, H. (2014). "Lysosomal exocytosis and lipid storage disorders". The Journal of Lipid Research. 55 (6): 995–1009. doi:10.1194/jlr.R046896. PMC 4031951Freely accessible. PMID 24668941. 
  8. Platt FM, Boland B, van der Spoel AC (November 2012). "The cell biology of disease: lysosomal storage disorders: the cellular impact of lysosomal dysfunction". The Journal of Cell Biology. 199 (5): 723–34. doi:10.1083/jcb.201208152. PMC 3514785Freely accessible. PMID 23185029. 
  9. He LQ, Lu JH, Yue ZY (May 2013). "Autophagy in ageing and ageing-associated diseases". Acta Pharmacologica Sinica. 34 (5): 605–11. doi:10.1038/aps.2012.188. PMC 3647216Freely accessible. PMID 23416930.