Location-regulated scaffold connecting MEK to RAF. Has very low protein kinase activity and can phosphorylate MAP2K1 at several Ser and Thr residues with very low efficiency (in vitro). Acts as MAP2K1/MEK1-dependent allosteric activator of BRAF; upon binding to MAP2K1/MEK1, dimerizes with BRAF and promotes BRAF-mediated phosphorylation of MAP2K1/MEK1 (PubMed:29433126). Interaction with BRAF enhances KSR2-mediated phosphorylation of MAP2K1 (in vitro). Blocks MAP3K8 kinase activity and MAP3K8-mediated signaling. Acts as a negative regulator of MAP3K3-mediated activation of ERK, JNK and NF- kappa-B pathways, inhibiting MAP3K3-mediated interleukin-8 production. {ECO:0000269|PubMed:12975377, ECO:0000269|PubMed:16039990, ECO:0000269|PubMed:21441910, ECO:0000269|PubMed:29433126}. This is the function of ENSG00000171435 (KSR2, kinase suppressor of ras 2).