Search results
Results from the WOW.Com Content Network
RAF is an acronym for Rapidly Accelerated Fibrosarcoma. [12] 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
Activated Ras then activates the protein kinase activity of a RAF kinase. [4] The RAF kinase phosphorylates and activates a MAPK/ERK Kinase (MEK1 or MEK2). The MEK phosphorylates and activates a mitogen-activated protein kinase (MAPK). RAF and MAPK/ERK are both serine/threonine-specific protein kinases. MEK is a serine/tyrosine/threonine kinase.
Similarly, both dual-specificity MAP kinase phosphatases and MAP-specific tyrosine phosphatases bind to MAP kinases through the same docking site. [34] [35] D-motifs can even be found in certain MAPK pathway regulators and scaffolds (e.g. in the mammalian JIP proteins). [citation needed] Other, less well characterised substrate-binding sites ...
Another protein kinase, Raf-1, was shown to phosphorylate a "MAP kinase-kinase", thus qualifying as a "MAP kinase kinase kinase". [4] 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 ...
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.
GAP eventually returns Ras to its inactive state. Activation of Ras has the potential to initiate three signaling pathways downstream of Ras: Ras→Raf→MAP kinase pathway, PI3 kinase pathway, and Ral pathway. Each pathway leads to the activation of transcription factors which enter the nucleus to alter gene expression. [9]
These are known as hormone-dependent breast cancers, as the kinase activation in these cancers is connected to exposure to both growth factors and estradiol. [8] Third, downstream effectors of mitogenic signaling are often mutated in cancer cells. An important mitogenic signaling pathway in humans is the Ras-Raf-MAPK pathway.
The gene was so named because the Sos protein that it encoded was found to operate downstream of the sevenless gene in Drosophila melanogaster in a Ras/MAP kinase pathway. [1] When sevenless is mutated or otherwise dysfunctional during development of the fly's ultraviolet light -sensitive compound eye , the seventh, central photoreceptor (R7 ...