Tektin 2 is required for central spindle microtubule organization and the completion of cytokinesis.
During anaphase, the nonkinetochore microtubules in the spindle midzone become compacted into the central spindle, a structure which is required to both initiate and complete cytokinesis. We show that Tektin 2 (Tek2) associates with the spindle poles throughout mitosis, organizes the spindle midzone microtubules during anaphase, and assembles into the midbody matrix surrounding the compacted midzone microtubules during cytokinesis. Tek2 small interfering RNA (siRNA) disrupts central spindle organization and proper localization of MKLP1, PRC1, and Aurora B to the midzone and prevents the formation of a midbody matrix. Video microscopy revealed that loss of Tek2 results in binucleate cell formation by aberrant fusion of daughter cells after cytokinesis. Although a myosin II inhibitor, blebbistatin, prevents actin-myosin contractility, the microtubules of the central spindle are compacted. Strikingly, Tek2 siRNA abolishes this actin-myosin-independent midzone microtubule compaction. Thus, Tek2-dependent organization of the central spindle during anaphase is essential for proper midbody formation and the segregation of daughter cells after cytokinesis.
Durcan
Thomas M
TM
Department of Biological Sciences and Notre Dame Integrated Imaging Facility, University of Notre Dame, Notre Dame, IN 46556, USA.
Halpin
Elizabeth S
ES
Rao
Trisha
T
Collins
Nicholas S
NS
Tribble
Emily K
EK
Hornick
Jessica E
JE
Hinchcliffe
Edward H
EH
D000199:Actins / Q000378:metabolism; D000818:Animals; D064107:Aurora Kinase B; D064127:Aurora Kinases; D016466:CHO Cells; D018797:Cell Cycle Proteins / Q000378:metabolism; D018385:Centrosome / Q000187:drug effects / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D048749:Cytokinesis / Q000187:drug effects; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D051379:Mice; D008868:Microtubule Proteins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism*
D000199:Actins; D018797:Cell Cycle Proteins; D006576:Heterocyclic Compounds, 4 or More Rings; D008868:Microtubule Proteins; D008869:Microtubule-Associated Proteins; D034741:RNA, Small Interfering; C044103:tektins; C472645:blebbistatin; C576924:Aurkb protein, mouse; D064107:Aurora Kinase B; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D009218:Myosins