Mitogen-Activated Protein Kinases (MAPKs) play a crucial role in cellular signaling, affecting proliferation, differentiation, and apoptosis. They are activated through a cascade involving phosphorylation by MAP kinase kinases and inactivated by MAP kinase phosphatases. This text delves into the MAPKs' functions, their classification into ERKs, JNKs, and p38 MAPKs, and the unique pathways of atypical MAPKs.
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MAPKs are a category of protein kinases that phosphorylate serine and threonine amino acids and play a crucial role in cellular responses to various stimuli
Proliferation and gene expression
MAPKs regulate cellular processes such as proliferation and gene expression
Differentiation and cell cycle progression
MAPKs also play a role in cellular processes such as differentiation and cell cycle progression
Survival and programmed cell death
MAPKs are involved in regulating cellular processes such as survival and programmed cell death
MAPKs are found exclusively in eukaryotic cells and are part of the CMGC kinase group
The three subfamilies of mammalian MAPKs are ERKs, JNKs, and p38 MAPKs, each activated by distinct stimuli
The specialized roles of MAPKs allow them to transduce a wide array of external signals into appropriate cellular responses
MAPKs play a crucial role in abiotic stress responses, particularly in plants which have a large number of MAPK genes to cope with environmental challenges
Classical MAPKs are initially in an inactive state and require sequential phosphorylation events to become catalytically active
The STE group of protein kinases promotes a conformational change in MAPKs through phosphorylation, leading to their activation
Classical MAPKs are activated by MAP2Ks, which are in turn activated by MAP3Ks, ensuring precise transmission of signals from the cell membrane to the nucleus or other intracellular destinations
Atypical MAPKs have unique activation mechanisms and often function within simpler two-tiered pathways
ERK3 and ERK4
ERK3 and ERK4 are examples of atypical MAPKs that are phosphorylated directly by certain members of the PAK family of kinases
Atypical MAPKs only require phosphorylation at a single residue in their activation loops, highlighting the adaptability and diversity of the MAPK enzyme family
The deactivation of MAPKs is crucial for maintaining precise control over cellular signaling
MKPs, part of the dual-specificity phosphatases family, are responsible for dephosphorylating both phosphotyrosine and phosphothreonine residues, thereby terminating MAPK activity
Certain tyrosine-specific phosphatases also play a role in inactivating MAPKs, ensuring tight regulation of cellular signaling
00
The ______ kinase group, which includes MAPKs, is found only in ______ cells and is essential for many cellular functions.
CMGC
eukaryotic
01
Research on MAPKs started with the discovery of ______ in mammals, and these kinases are known to play a role in ______ stress responses in plants.
ERK1
abiotic
02
ERK activation stimuli
ERKs activated by growth factors, mitogens.
