An intramolecular interaction between the FHA domain and a coiled coil negatively regulates the kinesin motor KIF1A.
Motor proteins not actively involved in transporting cargoes should remain inactive at sites of cargo loading to save energy and remain available for loading. KIF1A/Unc104 is a monomeric kinesin known to dimerize into a processive motor at high protein concentrations. However, the molecular mechanisms underlying monomer stabilization and monomer-to-dimer transition are not well understood. Here, we report an intramolecular interaction in KIF1A between the forkhead-associated (FHA) domain and a coiled-coil domain (CC2) immediately following the FHA domain. Disrupting this interaction by point mutations in the FHA or CC2 domains leads to a dramatic accumulation of KIF1A in the periphery of living cultured neurons and an enhancement of the microtubule (MT) binding and self-multimerization of KIF1A. In addition, point mutations causing rigidity in the predicted flexible hinge disrupt the intramolecular FHA-CC2 interaction and increase MT binding and peripheral accumulation of KIF1A. These results suggest that the intramolecular FHA-CC2 interaction negatively regulates KIF1A activity by inhibiting MT binding and dimerization of KIF1A, and point to a novel role of the FHA domain in the regulation of kinesin motors.
Lee
Jae-Ran
JR
National Creative Research Initiative Center for Synaptogenesis and Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
Shin
Hyewon
H
Choi
Jeonghoon
J
Ko
Jaewon
J
Kim
Seho
S
Lee
Hyun Woo
HW
Kim
Karam
K
Rho
Seong-Hwan
SH
Lee
Jun Hyuck
JH
Song
Hye-Eun
HE
Eom
Soo Hyun
SH
Kim
Eunjoon
E
D000818:Animals; D002478:Cells, Cultured; D006801:Humans; D016547:Kinesins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D017354:Point Mutation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
C094065:KIF1A protein, human; D020409:Molecular Motor Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D016547:Kinesins