MAPK

A broad category of serine-threonine kinases which regulate a broad range of cellular functions.
MAPK groups
• ERK—ERK1, ERK2.
• c-Jun N-terminal kinases
– JNK1 = MAPK8;
– JNK2 = MAPK9;
– JNK3 = MAPK10.
• p38 isoforms—MAPK11, MAPK12, MAPK13, MAPK14.
• ERK5—MAPK7.
• ERK3, ERK4—MAPK6, MAPK4.
• ERK7/8—MAPK15.
ERK = Extracellular signal-regulated kinases.
ERK 1 and ERK 2 transduce signals from growth factors and are key in regulating differentiation and proliferation in many cell types. Upon activation by MEK, ERK1 and ERK2 translocate to the nucleus where they phosphorylate transcription factors such as Elk1 and downstream kinases—e.g., p90 RSK, JNK 1 = MAPK8; JNK2 = MAPK 9; and JNK3 = MAPK 10 (sometimes known as SAPKs, or stress-activated kinases) and the p38.
MAPKs (alpha-, beta-, delta- and gamma- isoforms) are activated by UV irradiation, inflammatory cytokines and hyperosmolarity. The p38 MAPKs are also activated by lipopolysaccharide. Dysregulation of MAPK kinase pathways has been associated with various diseases, including cancer (ERK), neurodegeneration (JNK) and inflammation (p38).

mitogen-activated protein kinase

MAPK

A signaling protein, i.e., a protein that circulates extracellularly influencing other cells to turn on the process of protein synthesis. These proteins have an effect on cellular replication and cellular death in inflammatory, ischemic, and malignant diseases.

protein kinase

An enzyme that activates or inactivates cell proteins or enzymes by adding a phosphate moiety, thereby changing cell functions.

mitogen-activated protein kinase

Abbreviation: MAPK
A signaling enzyme, i.e., one that circulates extracellularly, influencing cells to begin protein manufacturing. They affect cellular replication and death in inflammatory, ischemic, and malignant diseases.