Phospholipase C

From Wikipedia, the free encyclopedia
Cleavage sites of phospholipases. Phospholipase C enzymes cut just before the phosphate attached to the R3 moiety.

Phospholipase C (PLC) is a class of enzymes that cleave phospholipids just before the phosphate group (see figure). It is most commonly taken to be synonymous with the human forms of this enzyme, which play an important role in eukaryotic cell physiology, in particular signal transduction pathways. Thirteen kinds of mammalian phospholipase C are classified into six isotypes (β, γ, δ, ε, ζ, η) according to structure.

Mammalian variants

Activation

Receptors that activate this pathway are mainly G protein-coupled receptors coupled to the Gαq subunit, including:

Other, minor, activators than Gαq are:

  • MAP kinase. Activators of this pathway include PDGF and FGF.[1]
  • βγ-complex of heterotrimeric G-proteins, as in a minor pathway of growth hormone release by growth hormone-releasing hormone.[2]

Effects

PLC cleaves the phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) into diacyl glycerol (DAG) and inositol 1,4,5-trisphosphate (IP3). DAG remains bound to the membrane, and IP3 is released as a soluble structure into the cytosol. IP3 then diffuses through the cytosol to bind to IP3 receptors, particular calcium channels in the smooth endoplasmic reticulum (ER). This causes the cytosolic concentration of calcium to increase, causing a cascade of intracellular changes and activity.[3] In addition, calcium and DAG together work to activate protein kinase C, which goes on to phosphorylate other molecules, leading to altered cellular activity.[3] End-effects include taste, tumor promotion, etc.[3]

In other organisms

Other phospholipase C enzymes have been identified in bacteria and in trypanosomes, each with its own EC number

See also

References

  1. ↑ 1.0 1.1 Walter F., PhD. Boron (2003). Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. p. 1300. ISBN 1-4160-2328-3.  Page 104
  2. ↑ GeneGlobe -> GHRH Signaling Retrieved on May 31, 2009
  3. ↑ 3.0 3.1 3.2 Alberts B, Lewis J, Raff M, Roberts K, Walter P (2002). Molecular biology of the cell (4th ed.). New York: Garland Science. ISBN 0-8153-3218-1. 
3.1.1: Carboxylic ester hydrolases
3.1.2: Thioesterase
3.1.3: Phosphatase
3.1.4: Phosphodiesterase
3.1.6: Sulfatase
Nuclease (includes
deoxyribonuclease and
ribonuclease)
3.1.11-16: Exonuclease
Exodeoxyribonuclease
Exoribonuclease
3.1.21-31: Endonuclease
Endodeoxyribonuclease
Endoribonuclease
either deoxy- or ribo-
  • B
  • enzm
  • 1.1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 10
    • 11
    • 13
    • 14
    • 15-18
  • 2.1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
      • 2.7.10
      • 11-12
    • 8
  • 3.1
      • 3.1.3.48
    • 2
    • 3
    • 4
      • 3.4.21
      • 22
      • 23
      • 24
    • 5
    • 6
    • 7
  • 4.1
    • 2
    • 3
    • 4
    • 5
    • 6
  • 5.1
    • 2
    • 3
    • 4
    • 99
  • 6.1-3
    • 4
    • 5-6
Precursor
Prostanoids
Leukotrienes
Ungrouped

M: MET

mt, k, c/g/r/p/y/i, f/h/s/l/o/e, a/u, n, m

k, cgrp/y/i, f/h/s/l/o/e, au, n, m, epon

m (A16/C10), i (k, c/g/r/p/y/i, f/h/s/o/e, a/u, n, m)

Anabolism
Catabolism

M: MET

mt, k, c/g/r/p/y/i, f/h/s/l/o/e, a/u, n, m

k, cgrp/y/i, f/h/s/l/o/e, au, n, m, epon

m (A16/C10), i (k, c/g/r/p/y/i, f/h/s/o/e, a/u, n, m)

This article is issued from Wikipedia. The text is available under the Creative Commons Attribution/Share Alike; additional terms may apply for the media files.