The JNK-interacting protein (JIP) group of scaffold proteins selectively mediates JNK signaling by aggregating specific components of the MAPK cascade to form a functional JNK signaling module (PubMed:12391307, PubMed:15767678). Regulates lysosomal positioning by acting as an adapter protein which links PIP4P1-positive lysosomes to the dynein-dynactin complex (By similarity). Assists PIKFYVE selective functionality in microtubule-based endosome-to-TGN trafficking (PubMed:19056739). Homodimer (By similarity). The homodimer interacts with ARF6, forming a heterotetramer (By similarity). Homooligomer (By similarity). Interacts with MAX, MAPK8, MAPK14, MAP3K3, MYC, and MAP2K4 (PubMed:12391307). Interacts with KNS2 (PubMed:15987681). Interaction with KNS2 is important in the formation of ternary complex with MAPK8 (PubMed:15767678). Interacts with PIP4P1 (By similarity). Interacts with PIKFYVE (PubMed:19056739). Perinuclear distribution in response to stress signals such as UV radiation. Highly expressed in brain, kidney, liver, heart. Up-regulated during neuronal differentiation. Phosphorylated by MAPK8 and MAPK14. Belongs to the JIP scaffold family. Extended N-terminus.