biostudies-literatureBenoit MPMHU.S. Department of Health & Human Services | NIH | National Institute of General Medical SciencesU.S. Department of Health & Human Services | NIH | National Institute of Neurological Disorders and StrokeU.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)U.S. Department of Health & Human Services | NIH | National Institute of Neurological Disorders and Stroke (NINDS)NINDS NIH HHSSimmons Family FoundationAgouron InstituteNIGMS NIH HHSNIH HHS5530https://www.ebi.ac.uk/biostudies/studies/S-EPMC11219953biostudies-literatureUnknown15(1)Mutations in the microtubule-associated motor protein KIF1A lead to severe neurological conditions known as KIF1A-associated neurological disorders (KAND). Despite insights into its molecular mechanism, high-resolution structures of KIF1A-microtubule complexes remain undefined. Here, we present 2.7-3.5 Å resolution structures of dimeric microtubule-bound KIF1A, including the pathogenic P305L mutant, across various nucleotide states. Our structures reveal that KIF1A binds microtubules in one- and two-heads-bound configurations, with both heads exhibiting distinct conformations with tight inter-head connection. Notably, KIF1A's class-specific loop 12 (K-loop) forms electrostatic interactions with the C-terminal tails of both α- and β-tubulin. The P305L mutation does not disrupt these interactions but alters loop-12's conformation, impairing strong microtubule-binding. Structure-function analysis reveals the K-loop and head-head coordination as major determinants of KIF1A's superprocessive motility. Our findings advance the understanding of KIF1A's molecular mechanism and provide a basis for developing structure-guided therapeutics against KAND.Nature communicationsCryo-EM unveils kinesin KIF1A's processivity mechanism and the impact of its pathogenic variant P305L.PMC11219953R01GM147332S10 OD019994R01NS114636SF349247R01 GM098469P41 GM103310GM103310R01 NS114636F00316R01 GM147332R01GM113164R01 GM113164Gennerich ASosa HAsenjo ABRao LBenoit MPMHfalseCryo-EM unveils kinesin KIF1A's processivity mechanism and the impact of its pathogenic variant P305L.Mutations in the microtubule-associated motor protein KIF1A lead to severe neurological conditions known as KIF1A-associated neurological disorders (KAND). Despite insights into its molecular mechanism, high-resolution structures of KIF1A-microtubule complexes remain undefined. Here, we present 2.7-3.5 Å resolution structures of dimeric microtubule-bound KIF1A, including the pathogenic P305L mutant, across various nucleotide states. Our structures reveal that KIF1A binds microtubules in one- and two-heads-bound configurations, with both heads exhibiting distinct conformations with tight inter-head connection. Notably, KIF1A's class-specific loop 12 (K-loop) forms electrostatic interactions with the C-terminal tails of both α- and β-tubulin. The P305L mutation does not disrupt these interactions but alters loop-12's conformation, impairing strong microtubule-binding. Structure-function analysis reveals the K-loop and head-head coordination as major determinants of KIF1A's superprocessive motility. Our findings advance the understanding of KIF1A's molecular mechanism and provide a basis for developing structure-guided therapeutics against KAND.2024-01-01T00:00:00Z2024 Jul2026-05-29T09:57:42.264Z2025-04-04T12:21:13.819ZS-EPMC112199533895602110.1038/s41467-024-48720-4