Mitogen-activated protein kinase

From Wikipedia, the free encyclopedia

MAP kinase activation
Mitogen
↓
MAP kinase kinase kinase (MAP3K or MKKK)
↓
MAP kinase kinase (MAP2K or MKK)
↓
MAP kinase
↓
further signalling

In cell biology, mitogen-activated protein (MAP) kinases (EC 2.7.11.24) are serine/threonine-specific protein kinases that respond to extracellular stimuli (mitogens) and regulate various cellular activities, such as gene expression, mitosis, differentiation, and cell survival/apoptosis ^[1].

MAPK is involved in the action of most nonnuclear oncogenes. It is responsible for cell response to growth factors such as BDNF or nerve growth factor.

1 Function
2 Groups
3 See also
4 External links
5 References
6 External links

[edit] Function

Extracellular stimuli lead to activation of a MAP kinase via a signaling cascade ("MAPK cascade") composed of MAP kinase, MAP kinase kinase (MKK or MAP2K), and MAP kinase kinase kinase (MKKK or MAP3K, EC 2.7.11.25)^[1].

A MAP3K that is activated by extracellular stimuli phosphorylates a MAP2K on its serine and threonine residues, and then this MAP2K activates a MAP kinase through phosphorylation on its serine and tyrosine residues. This MAP kinase signaling cascade has been evolutionarily well-conserved from yeast to mammals.

[edit] Groups

To date, four distinct groups of MAPKs have been characterized in mammals:

extracellular signal-regulated kinases (ERKs). The ERKs (also known as classical MAP kinases) signaling pathway is preferentially activated in response to growth factors and phorbol ester (a tumor promoter), and regulates cell proliferation and cell differentiation.
c-Jun N-terminal kinases (JNKs), also known as stress-activated protein kinases (SAPKs).
p38 isoforms. Both JNK and p38 signaling pathways are responsive to stress stimuli, such as cytokines, ultraviolet irradiation, heat shock, and osmotic shock, and are involved in cell differentiation and apoptosis.
ERK5. ERK5, which has been found recently, is activated both by growth factors and by stress stimuli, and it participates in cell proliferation.

[edit] See also

MAPK/ERK pathway
Anthra(1,9-cd)pyrazol-6(2H)-one - inhibitor

[edit] External links

Table of names for mitogen-activated kinases.
MAPK cascade picture: http://wwwmgs.bionet.nsc.ru/mgs/gnw/genenet/viewer/MAPK%20cascade.html
Seger R, Krebs E (1995). "The MAPK signaling cascade". FASEB J 9 (9): 726-35. PMID 7601337.

[edit] References

^ ^a ^b Pearson G, Robinson F, Beers Gibson T, Xu BE, Karandikar M, Berman K and Cobb MH. (2001) "Mitogen-activated protein (MAP) kinase pathways: regulation and physiological functions" in Endocr Rev Volume 22, pages 153-183. Entrez PubMed 11294822.