Cell and molecular biology of spindle poles and NuMA.
Mitotic and meiotic cells contain a bipolar spindle apparatus of microtubules and associated proteins. To arrange microtubules into focused spindle poles, different mechanisms are used by various organisms. Principally, two major pathways have been characterized: nucleation and anchorage of microtubules at preexisting centers such as centrosomes or spindle pole bodies, or microtubule growth off the surface of chromosomes, followed by sorting and focusing into spindle poles. These two mechanisms can even be found in cells of the same organism: whereas most somatic animal cells utilize the centrosome as an organizing center for spindle microtubules, female meiotic cells build an acentriolar spindle apparatus. Most interestingly, the molecular components that drive acentriolar spindle pole formation are also present in cells containing centrosomes. They include microtubule-dependent motor proteins and a variety of structural proteins that regulate microtubule orientation, anchoring, and stability. The first of these spindle pole proteins, NuMA, had already been identified more than 20 years ago. In addition, several new proteins have been characterized more recently. This review discusses their role during spindle formation and their regulation in the cell cycle.
Fant
Xavier
X
Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, United Kingdom.
Merdes
Andreas
A
Haren
Laurence
L
D000818:Animals; D034961:Antigens, Nuclear; D018797:Cell Cycle Proteins; D018385:Centrosome / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D006801:Humans; D008540:Meiosis / Q000502:physiology; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis / Q000502:physiology; D020409:Molecular Motor Proteins / Q000378:metabolism; D015530:Nuclear Matrix / Q000378:metabolism; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D008941:Spindle Apparatus / Q000502:physiology; D020931:ran GTP-Binding Protein / Q000378:metabolism
D034961:Antigens, Nuclear; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D020409:Molecular Motor Proteins; C050045:NUMA1 protein, human; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins; D020931:ran GTP-Binding Protein