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:14743216). Regulates lysosomal positioning by acting as an adapter protein which links PIP4P1-positive lysosomes to the dynein-dynactin complex (PubMed:29146937). Assists PIKFYVE selective functionality in microtubule-based endosome-to-TGN trafficking (By similarity). May play a role in spermatozoa-egg-interaction. Homodimer (PubMed:19644450). The homodimer interacts with ARF6, forming a heterotetramer (PubMed:19644450). Homooligomer (PubMed:19644450). Interacts with MAX, MAPK14, MAP3K3, MYC, KNS2 and MAP2K4 (By similarity). Interaction with KNS2 is important in the formation of ternary complex with MAPK8 (By similarity). Interacts with NFKB1 (PubMed:14743216). Interacts with PIP4P1 (PubMed:29146937). Interacts with PIKFYVE (By similarity). Interacts with MAPK8, MAPK9, MAPK10. Perinuclear distribution in response to stress signals such as UV radiation. Associated with the plasma membrane of the acrosomal compartment and also localizes in the acrosome matrix. Expressed only in testis on the round spermatids of stage I, II and II. Absent in spermatogonia and spermatocyte. Expressed in testis and in acute myeloid leukemia (AML) patients. Expressed in testis. Increased in systemic sclerosis fibroblasts. Phosphorylated by MAPK8 and MAPK14. Due to intron retention. Belongs to the JIP scaffold family. Probable cloning artifact. Probable cloning artifact. Contaminating sequence. Sequence of unknown origin in the C-terminal part. Truncated N-terminus. Extended N-terminus. Unlikely isoform. Aberrant splicing. Truncated N-terminus.