Location-regulated scaffolding protein connecting MEK to RAF. Promotes MEK and RAF phosphorylation and activity through assembly of an activated signaling complex. By itself, it has no demonstrated kinase activity.
Specificity
Natural and recombinant Human Kinase suppressor of Ras 1
Subcellular Location
Cytoplasm Membrane Peripheral membrane protein Endoplasmic reticulum membrane In unstimulated cells, where the phosphorylated form is bound to a 14-3-3 protein, sequestration in the cytoplasm occurs. Following growth factor treatment, the protein is free for membrane translocation, and it moves from the cytoplasm to the cell periphery.
Interacts with HSPCA/HSP90, YWHAB/14-3-3, CDC37, MAP2K/MEK, MARK3, PPP2R1A and PPP2CA. Also interacts with RAF and MAPK/ERK, in a Ras-dependent manner (By similarity). The binding of 14-3-3 proteins to phosphorylated KSR prevents the membrane localization. Interacts with isoform 1 of VRK2.