May play a role in action potential conduction in myelinated cells through the organization of molecular complexes at nodes of Ranvier and axon initial segments (PubMed:25950943). May also play a role in axon outgrowth and guidance (By similarity). Homooligomer (via coiled coil domain). Interacts (via IQ domain) with calmodulin; the interaction is direct and lost in presence of calcium (By similarity). Interacts with ANK3 (via ANK repeats); required for localization at axon initial segments (AIS) and nodes of Ranvier (PubMed:25950943). Interacts with SPTBN4. Interacts with KCNQ2 and KCNQ3 (By similarity). Localizes to the axon initial segments (AIS) and nodes of Ranvier of neurons and is absent from dendrites. Highly expressed in brain and to a lower extent in heart and kidney. Isoform IQCJ-SCHIP1-1 and isoform IQCJ-SCHIP1-2 are expressed in fetal brain, kidney, spleen and skeletal muscle. Isoform IQCJ-SCHIP1-2 is also detected in fetal heart and lung. Based on a naturally occurring readthrough transcript which produces an IQCJ-SCHIP1 fusion protein. Based on a naturally occurring readthrough transcript which produces an IQCJ-SCHIP1 fusion protein.