KSR1
KSR1 (kinase suppressor of Ras 1, also known as RSU2 and KSR) is a member of the TKL Ser/Thr protein kinase family that acts as part of a multiprotein signalling complex. It promotes RAF phosphorylation and activation of downstream MAP kinases. Browse Assay Genie's current range of KSR1 research reagents below, or read on for the biology behind the target.
KSR1 is part of a multiprotein signalling complex that promotes phosphorylation of RAF family members and activation of downstream MAP kinases. Independently of its own kinase activity, it acts as a MAP2K1/MEK1- and MAP2K2/MEK2-dependent allosteric activator of BRAF. On binding MEK1 or MEK2, KSR1 dimerises with BRAF and promotes BRAF-mediated phosphorylation of MEK1 and/or MEK2. Through this route it promotes activation of MAPK1 and/or MAPK3, in response to both EGF and cAMP.
The KSR1 protein belongs to the protein kinase superfamily and the TKL Ser/Thr protein kinase family. HGNC places the KSR1 gene in the RAF family and in the pseudokinase group, which fits the uncertainty over its catalytic role. Some protein kinase activity has been detected in vitro, but its physiological relevance is unknown, and the kinase activity of KSR1 is regarded as unsure. NCBI Gene annotates it as enabling 14-3-3 protein binding and ATP binding, and as involved in positive regulation of the MAPK cascade.
KSR1 is found in the cytoplasm and at several membranes, including the cell membrane, ruffle membrane and endoplasmic reticulum membrane. NCBI Gene describes it as located in the cytosol, endoplasmic reticulum and membrane, and as part of a protein-containing complex. The original name, kinase suppressor of ras, is retained as a previous HGNC name. KSR1 is implicated in breast adenocarcinoma and is listed as a biomarker of breast cancer. The mouse ortholog is Ksr1, and a related family member is KSR2.
KSR1 promotes activation of MAPK1 and MAPK3 in response to EGF and cAMP, making it a useful node for studying MAPK cascade regulation.
KSR1 allosterically activates BRAF in a MEK-dependent manner, offering a model for RAF dimerisation and MEK phosphorylation.
The physiological relevance of KSR1 kinase activity is unknown, so it is a focus for studies of non-catalytic kinase functions.
KSR1 is implicated in breast adenocarcinoma and described as a biomarker of breast cancer, supporting its use in cancer research.
KSR1 is part of a multiprotein complex that promotes RAF phosphorylation and activation of downstream MAP kinases. It binds MEK1 or MEK2, dimerises with BRAF and promotes BRAF-mediated MEK phosphorylation, which supports activation of MAPK1 and MAPK3 in response to EGF and cAMP.
KSR1 is also known as KSR and RSU2. Its HGNC full name is kinase suppressor of ras 1, and the previous name was kinase suppressor of ras. The UniProt entry for the human protein is Q8IVT5, and the mouse ortholog is called Ksr1.
Its kinase activity is unsure. Some activity has been detected in vitro, but its physiological relevance is unknown, and HGNC lists it among pseudokinases. NCBI Gene reports that KSR1 is implicated in breast adenocarcinoma and is a biomarker of breast cancer.
Other kinase suppressor of Ras family members and related MAPK pathway targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt Q8IVT5; product specifications from Assay Genie datasheets.