A mitotic kinesin-6, Pav-KLP, mediates interdependent cortical reorganization and spindle dynamics in Drosophila embryos.
We investigated the role of Pav-KLP, a kinesin-6, in the coordination of spindle and cortical dynamics during mitosis in Drosophila embryos. In vitro, Pav-KLP behaves as a dimer. In vivo, it localizes to mitotic spindles and furrows. Inhibition of Pav-KLP causes defects in both spindle dynamics and furrow ingression, as well as causing changes in the distribution of actin and vesicles. Thus, Pav-KLP stabilizes the spindle by crosslinking interpolar microtubule bundles and contributes to actin furrow formation possibly by transporting membrane vesicles, actin and/or actin regulatory molecules along astral microtubules. Modeling suggests that furrow ingression during cellularization depends on: (1) a Pav-KLP-dependent force driving an initial slow stage of ingression; and (2) the subsequent Pav-KLP-driven transport of actin- and membrane-containing vesicles to the furrow during a fast stage of ingression. We hypothesize that Pav-KLP is a multifunctional mitotic motor that contributes both to bundling of interpolar microtubules, thus stabilizing the spindle, and to a biphasic mechanism of furrow ingression by pulling down the furrow and transporting vesicles that deliver new material to the descending furrow.
Sommi
Patrizia
P
LCCB, Center for Genetics and Development, University of California at Davis, Davis, CA 95616, USA.
Ananthakrishnan
Revathi
R
Cheerambathur
Dhanya K
DK
Kwon
Mijung
M
Morales-Mulia
Sandra
S
Brust-Mascher
Ingrid
I
Mogilner
Alex
A
D000199:Actins / Q000378:metabolism; D000818:Animals; D019138:Antibodies, Blocking / Q000008:administration & dosage; D004330:Drosophila / Q000166:cytology* / Q000196:embryology; D029721:Drosophila Proteins / Q000276:immunology / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D005453:Fluorescence; D018613:Microscopy, Confocal; D008869:Microtubule-Associated Proteins / Q000276:immunology / Q000378:metabolism*; D022101:Microtubule-Organizing Center / Q000187:drug effects; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis / Q000187:drug effects; D021381:Protein Transport; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D050257:Tubulin Modulators / Q000276:immunology / Q000378:metabolism*
D000199:Actins; D019138:Antibodies, Blocking; D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins; D050257:Tubulin Modulators; C490516:pav protein, Drosophila