A bipolar kinesin.
Chromosome segregation during mitosis depends on the action of the mitotic spindle, a self-organizing, bipolar protein machine which uses microtubules (MTs) and their associated motors. Members of the BimC subfamily of kinesin-related MT-motor proteins are believed to be essential for the formation and functioning of a normal bipolar spindle. Here we report that KRP130, a homotetrameric BimC-related kinesin purified from Drosophila melanogaster embryos, has an unusual ultrastructure. It consists of four kinesin-related polypeptides assembled into a bipolar aggregate with motor domains at opposite ends, analogous to a miniature myosin filament. Such a bipolar 'minifilament' could crosslink spindle MTs and slide them relative to one another. We do not know of any other MT motors that have a bipolar structure.
Kashina
A S
AS
Section of Molecular and Cellular Biology, University of California, Davis 95616, USA.
Baskin
R J
RJ
Cole
D G
DG
Wedaman
K P
KP
Saxton
W M
WM
Scholey
J M
JM
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D004331:Drosophila melanogaster; D016547:Kinesins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry*; D011487:Protein Conformation; D008941:Spindle Apparatus / Q000737:chemistry
D000906:Antibodies; D002135:Calcium-Binding Proteins; D009124:Muscle Proteins; C074152:kinesin-II; D016547:Kinesins