regulatory coiled-coil domain found in the kinesin-like KIF21 family
The KIF21 family includes KIF21A and KIF21B. KIF21A (also called kinesin-like protein KIF2, or renal carcinoma antigen NY-REN-62) is a microtubule-binding motor protein involved in neuronal axonal transport. It works as a microtubule stabilizer that regulates axonal morphology, suppressing cortical microtubule dynamics in neurons. Mutations in KIF21A cause congenital fibrosis of the extraocular muscles type 1 (CFEOM1). In vitro, it has a plus-end directed motor activity. KIF21B is a plus-end directed microtubule-dependent motor protein which displays processive activity. It is involved in regulation of microtubule dynamics, synapse function, and neuronal morphology, including dendritic tree branching and spine formation. KIF21B plays a role in learning and memory. It is involved in the delivery of gamma-aminobutyric acid (GABA(A)) receptors to the cell surface. This model corresponds to the regulatory coiled-coil domain of KIF21A/KIF21B, which folds into an intramolecular antiparallel coiled-coil monomer in solution but crystallizes into a dimeric domain-swapped antiparallel coiled-coil.