Dr. Dolittle and the making of the mitotic spindle.
The intrinsic polarity of microtubules within cells is exploited each time cells divide. Kinesins, microtubule-associated motor proteins, are required to execute the dramatic events of mitosis: bipolar spindle assembly, metaphase chromosome alignment, anaphase chromosome segregation, and separation of spindle poles prior to cytokinesis. Surprisingly, kinesin-related proteins have been found to move in either "plus-ward" or "minus-ward" directions along microtubules. Evidence from genetic analyses of simple eukaryotes and in vitro activity assays supports the notion that certain subfamilies of kinesin-related proteins provide antagonistic activities necessary to balance mitotic forces. A recent study by Sharp et al.((1)) sheds further light on the subject by exploiting the genetics and cytology of the fruit fly embryo.
Heck
M M
MM
University of Edinburgh, Institute of Cell and Molecular Biology, Michael Swann Building, Mayfield Road, Edinburgh EH9 3JR, UK. margarete.heck@ed.ac.uk
D000818:Animals; D002453:Cell Cycle / Q000502:physiology*; D016547:Kinesins / Q000502:physiology; D008870:Microtubules / Q000502:physiology / Q000648:ultrastructure; D008954:Models, Biological; D008941:Spindle Apparatus / Q000502:physiology* / Q000648:ultrastructure*
D016547:Kinesins