Molecular scaffold protein for various multimeric protein complexes. Acts as a module in the assembly of a multicomponent scaffold for the ERK pathway, linking ERK responses to specific agonists. At low concentrations it enhances ERK activation, whereas high concentrations lead to the inhibition of ERK activation. Also involved in response to hypoxia by acting as a negative regulator of HIF1A/HIF-1-alpha via its interaction with EGLN3/PHD3. May promote degradation of HIF1A. May act by recruiting signaling complexes to a specific upstream activator (By similarity). May also be involved in pre-mRNA splicing. Participates in tight junction development by regulating apico-basal polarity, a key step in tissue development and organization. Mechanistically, regulates the translocation of PAR6-aPKC from the cytoplasm to the apical surface by acting as an adapter between PARD6B AND CRB3 (PubMed:23439680). Acts also as a negative regulator of mTORC1 under nutrient-rich conditions by binding to the active Rag GTPases to inhibit mTORC1 localization to the lysosome and phosphorylation of downstream targets. This facilitates constitutive basal autophagy during nutrient availability (PubMed:38103557).
