ELKS/RAB6-interacting/CAST family member 1 is a protein that in humans is encoded by the ERC1 gene. The name ELKS is derived from "protein rich in the amino acids E, L, K and S". The protein encoded by this gene is a member of a family of RIM-binding proteins. RIMs are active zone proteins that regulate neurotransmitter release. This gene has been found fused to the receptor-type tyrosine kinase gene RET by gene rearrangement due to the translocation t (10;12) (q11;p13). Multiple transcript variants encoding different isoforms have been found for this gene. ELKS has been reported to direct vesicles with RAB6A to melanosomes. Regulatory subunit of the IKK complex. Probably recruits IkappaBalpha/NFKBIA to the complex. May be involved in the organization of the cytomatrix at the nerve terminals active zone (CAZ) which regulates neurotransmitter release. May be involved in vesicle trafficking at the CAZ. May be involved in Rab-6 regulated endosomes to Golgi transport. Widely expressed. Isoform 2 and isoform 4 are abundantly expressed in brain. Isoform 1 and isoform 3 are predominantly expressed in testis and thyroid, and isoform 1 predominates in other tissues tested.