Direct regulation of microtubule dynamics by KIF17 motor and tail domains.
KIF17 is a kinesin-2 family motor that interacts with EB1 at microtubule (MT) plus-ends and contributes to MT stabilization in epithelial cells. The mechanism by which KIF17 affects MTs and how its activity is regulated are not yet known. Here, we show that EB1 and the KIF17 autoinhibitory tail domain (KIF17-Tail) interacted competitively with the KIF17 catalytic motor domain (K370). Both EB1 and KIF17-Tail decreased the K0.5MT of K370, with opposing effects on MT-stimulated ATPase activity. Importantly, K370 had independent effects on MT dynamic instability, resulting in formation of long MTs without affecting polymerization rate or total polymer mass. K370 also inhibited MT depolymerization induced by dilution in vitro and by nocodazole in cells, suggesting that it acts by protecting MT plus-ends. Interestingly, KIF17-Tail bound MTs and tubulin dimers, delaying initial MT polymerization in vitro and MT regrowth in cells. However, neither EB1 nor KIF17-Tail affected K370-mediated MT polymerization or stabilization significantly in vitro, and EB1 was dispensable for MT stabilization by K370 in cells. Thus, although EB1 and KIF17-Tail may coordinate KIF17 catalytic activity, our data reveal a novel and direct role for KIF17 in regulating MT dynamics.
From the Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, New York 10065.
Bipul R
BR
Acharya
From the Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, New York 10065.
Cedric
C
Espenel
From the Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, New York 10065. Electronic address: gek2006@med.cornell.edu.
Geri
G
Kreitzer
D000818:Animals; D018938:Caco-2 Cells; D002384:Catalysis; D002417:Cattle; D006801:Humans; D016547:Kinesins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization / Q000502:physiology*; D017434:Protein Structure, Tertiary; D014404:Tubulin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
C485813:KIF17 protein, human; C500985:MAPRE1 protein, human; D008869:Microtubule-Associated Proteins; D014404:Tubulin; D016547:Kinesins
Cytoskeleton; Epithelial Cell; Kinesin; Microtubules; Protein Domains