Abstract
Mutations in the Kinesin-3 motor KIF1A, a microtubule (MT)-associated motor protein, cause devastating neurodevelopmental and neurodegenerative diseases termed KIF1A-associated neurological disorders (KAND). While the mechanism of KIF1A is increasingly understood, high resolution (<4 Å) structural information of KIF1A-MT complexes is lacking. Here, we present 2.7-3.4 Å resolution structures of dimeric MT-bound wild-type (WT) KIF1A and the pathogenic P305L mutant as a function of the nucleotide state. Our structures reveal that 1) the KIF1A dimer binds MTs in one- and two-heads-bound states, 2) that both MT-bound heads assume distinct conformations with tight inter-head connection, 3) the position and conformation of the class-specific loop 12 (the K-loop), and 4) that the P305L mutation causes structural changes in the K-loop that result in a weakly MT-bound state. Motivated by our structural insights, we performed structure-function studies that reveal that both the K-loop and head-head coordination are major determinants of KIF1A’s superprocessive motility. Our work provides key insights into the mechanism of KIF1A and provides near-atomic structures of WT and mutant KIF1A for future structure-guided drug-design approaches to treat KAND.
Full Text Availability
The license terms selected by the author(s) for this preprint version do not permit archiving in PMC. The full text is available from the preprint server.