Search results
Results from the WOW.Com Content Network
Mitogen-activated protein kinase (MAPK) networks are the pathways and signaling of MAPK, which is a protein kinase that consists of amino acids serine and threonine. [1] MAPK pathways have both a positive and negative regulation in plants. A positive regulation of MAPK networks is to help in assisting with stresses from the environment.
Despite the high number of MAPK genes, MAPK pathways of higher plants were studied less than animal or fungal ones. Although their signaling appears very complex, the MPK3, MPK4 and MPK6 kinases of Arabidopsis thaliana are key mediators of responses to osmotic shock, oxidative stress, response to cold and involved in anti-pathogen responses.
The signal that starts the MAPK/ERK pathway is the binding of extracellular mitogen to a cell surface receptor.This allows a Ras protein (a Small GTPase) to swap a GDP molecule for a GTP molecule, flipping the "on/off switch" of the pathway.
Perhaps the best characterized MAP3K are the members of the oncogenic RAF family (RAF1, BRAF, ARAF), which are effectors of mitogenic ras signaling and which activate the ERK1/2 (MAPK3/MAPK1) pathway, through activation of MEK1(MAP2K1) and MEK2(MAP2K2). The JNKs are regulated by the MEKK 1/4, MLK 2/3, and ASK 1 MAPKKKs.
The MAP kinase-kinase, which activates ERK, was named "MAPK/ERK kinase" . [5] Receptor-linked tyrosine kinases, Ras, Raf, MEK, and MAPK could be fitted into a signaling cascade linking an extracellular signal to MAPK activation. [6] See: MAPK/ERK pathway. Transgenic gene knockout mice lacking MAPK1 have major defects in early development. [7]
MAPK phosphatases (MKPs) are the largest class of phosphatases involved in down-regulating Mitogen-activated protein kinases (MAPK) signaling. [1] [2] MAPK signalling pathways regulate multiple features of development and homeostasis. [3] [4] This can involve gene regulation, cell proliferation, programmed cell death and stress responses. [5]
Mitogen-activated protein kinase kinase (also known as MAP2K, MEK, MAPKK) is a dual-specificity kinase enzyme which phosphorylates mitogen-activated protein kinase (MAPK). MAP2K is classified as EC 2.7.12.2. There are seven genes: MAP2K1 (a.k.a. MEK1) MAP2K2 (a.k.a. MEK2) MAP2K3 (a.k.a. MKK3) MAP2K4 (a.k.a. MKK4) MAP2K5 (a.k.a. MKK5) MAP2K6 (a ...
RAF kinases participate in the RAS-RAF-MEK-ERK signal transduction cascade, also referred to as the mitogen-activated protein kinase (MAPK) cascade. [11] Activation of RAF kinases requires interaction with RAS-GTPases. The three RAF kinase family members are: A-RAF; B-RAF; c-Raf