RT Journal Article SR Electronic T1 KIF18A's neck linker permits navigation of microtubule-bound obstacles within the mitotic spindle JF Life Science Alliance JO Life Sci. Alliance FD Life Science Alliance LLC SP e201800169 DO 10.26508/lsa.201800169 VO 2 IS 1 A1 Heidi LH Malaby A1 Dominique V Lessard A1 Christopher L Berger A1 Jason Stumpff YR 2019 UL https://www.life-science-alliance.org/content/2/1/e201800169.abstract AB KIF18A (kinesin-8) is required for mammalian mitotic chromosome alignment. KIF18A confines chromosome movement to the mitotic spindle equator by accumulating at the plus-ends of kinetochore microtubule bundles (K-fibers), where it functions to suppress K-fiber dynamics. It is not understood how the motor accumulates at K-fiber plus-ends, a difficult feat requiring the motor to navigate protein dense microtubule tracks. Our data indicate that KIF18A's relatively long neck linker is required for the motor's accumulation at K-fiber plus-ends. Shorter neck linker (sNL) variants of KIF18A display a deficiency in accumulation at the ends of K-fibers at the center of the spindle. Depletion of K-fiber–binding proteins reduces the KIF18A sNL localization defect, whereas their overexpression reduces wild-type KIF18A's ability to accumulate on this same K-fiber subset. Furthermore, single-molecule assays indicate that KIF18A sNL motors are less proficient in navigating microtubules coated with microtubule-associated proteins. Taken together, these results support a model in which KIF18A's neck linker length permits efficient navigation of obstacles to reach K-fiber ends during mitosis.