Associates with microtubules and may play a role in the microtubule-dependent transport of the GABA-B receptor. May play a role in JAK1 signaling and regulate microtubule cytoskeleton rearrangements. Homodimer. Forms a complex with GABBR1 and KIF5B/kinesin-1. Interacts with JAK1 and TYK2. Colocalizes with the microtubule network. Localizes to the cell body and neurites of hippocampal neurons where it accumulates in granules. Localizes to the tail and to a lower extent to the head of sperm cells. Predominantly expressed in neural tissues and lymphoid cells (at protein level). Isoform 2, isoform 3 and isoform 4 are specifically expressed in brain and retina. Isoform 1 and isoform 5 are also detected in liver, lung and skeletal muscle. Also detected in testis and to a lower extent spleen and intestine. Dubious isoform produced through aberrant splice sites. Dubious isoform produced through aberrant splice sites. Belongs to the JAKMIP family. Was originally thought to bind single-stranded RNA molecules and regulate GABA-B receptor expression. Truncated C-terminus. Wrong choice of CDS.