title: The dual function of KSR1: a pseudokinase and beyond.
abstract: Protein kinases play a pivotal role in regulating many aspects of biological processes, including development, differentiation and cell death. Within the kinome, 48 kinases (~10%) are classified as pseudokinases owing to the fact that they lack at least one conserved catalytic residue in their kinase domain. However, emerging evidence suggest that some pseudokinases, even without the ability to phosphorylate substrates, are regulators of multiple cellular signalling pathways. Among these is KSR1 (kinase suppressor of Ras 1), which was initially identified as a novel kinase in the Ras/Raf pathway. Subsequent studies showed that KSR1 mainly functions as a platform to assemble different cellular components thereby facilitating signal transduction. In the present article, we discuss recent findings regarding KSR1, indicating that it has dual activity as an active kinase as well as a pseudokinase/scaffolding protein. Moreover, the biological functions of KSR1 in human disorders, notably in malignancies, are also reviewed.
authors.affiliation: Department of Surgery and Cancer, Division of Cancer, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 ONN, UK. h.zhang10@imperial.ac.uk
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Chuay Yeng
authors.initials: CY
authors.lastname: Koo
authors.forename: Justin
authors.initials: J
authors.lastname: Stebbing
authors.forename: Georgios
authors.initials: G
authors.lastname: Giamas
mesh_terms: D006801:Humans; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf
chemical_list: D011494:Protein Kinases; C097199:KSR-1 protein kinase; D019908:Proto-Oncogene Proteins c-raf