Centrosomes play several fundamental roles in the cell including the nucleation and organization of microtubules for spindle assembly and molecular motor-driven processes. They also anchor important regulatory activities that control centrosome and spindle function and may contribute to tumorigenesis through the organization of dysfunctional spindles that fail to segregate chromosomes properly. The overall objective of our research is to understand the molecular basis of centrosome function. Our general strategy is to focus on the function of pericentrin, a centrosome protein I identified in six years ago, using a combination of molecular, biochemical and morphological strategies. Over the past budget period, we have made significant progress in understanding pericentrin function. We determined that pericentrin forms a complex with microtubule nucleating proteins including gamma tubulin and is in close proximity with gamma tubulin at the centrosome. We found that pericentrin interacts directly with cytoplasmic dynein light intermediate chain 1 and that dynein mediates assembly of pericentrin and gamma tubulin onto centrosomes. Moreover, pericentrin overexpression disrupts dynein localization, causes spindle defects and creates aneuploid cells. In collaboration with Dr. J. Scott (Vollum Inst.), we showed that pericentrin anchors kinase A to centrosomes and that this interaction is important for spindle function. Based on the observations outlined above, we have formulated a model in which pericentrin serves to specifically transport, anchor and organize important functional and regulatory activities at the centrosome. Over the next budget period we will continue to study the role of pericentrin and pericentrin- interacting proteins in centrosome and spindle function using both in vivo approaches and in vitro reconstitution. In the first aim of this proposal we will investigate the role of pericentrin in the assembly of microtubule nucleating complexes onto centrosomes. We will use cytoplasmic extracts prepared from Xenopus eggs to test the ability of protein complexes containing pericentrin to mediate the assembly of gamma tubulin complexes onto centrosomes in vitro. The second objective is to determine the significance of the interaction between pericentrin and dynein light intermediate chain 1. Specifically, we will use a dominant negative form of pericentrin to uncouple the pericentrin-dynein light intermediate chain interaction and examine the role of this interaction in centrosome assembly and spindle organization.
The third aim i s to identify and characterize other pericentrin-interacting proteins and to characterize a novel centriole protein which, like pericentrin, was identified using autoimmune sera.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Cell Development and Function Integrated Review Group (CDF)
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Deatherage, James F
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University of Massachusetts Medical School Worcester
Other Basic Sciences
Schools of Medicine
United States
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Hung, Hui-Fang; Hehnly, Heidi; Doxsey, Stephen (2016) The Mother Centriole Appendage Protein Cenexin Modulates Lumen Formation through Spindle Orientation. Curr Biol 26:793-801
Vertii, Anastassiia; Bright, Alison; Delaval, Benedicte et al. (2015) New frontiers: discovering cilia-independent functions of cilia proteins. EMBO Rep 16:1275-87
Vertii, Anastassiia; Zimmerman, Wendy; Ivshina, Maria et al. (2015) Centrosome-intrinsic mechanisms modulate centrosome integrity during fever. Mol Biol Cell 26:3451-63
Hung, Hui-Fang; Hehnly, Heidi; Doxsey, Stephen (2015) Methods to analyze novel liaisons between endosomes and centrosomes. Methods Cell Biol 130:47-58
de Souza, Edmarcia Elisa; Hehnly, Heidi; Perez, Arina Marina et al. (2015) Human Nek7-interactor RGS2 is required for mitotic spindle organization. Cell Cycle 14:656-67
Hehnly, Heidi; Doxsey, Stephen (2014) Rab11 endosomes contribute to mitotic spindle organization and orientation. Dev Cell 28:497-507
Chen, Chun-Ting; Hehnly, Heidi; Yu, Qing et al. (2014) A unique set of centrosome proteins requires pericentrin for spindle-pole localization and spindle orientation. Curr Biol 24:2327-2334
Chen, Chun-Ting; Ettinger, Andreas W; Huttner, Wieland B et al. (2013) Resurrecting remnants: the lives of post-mitotic midbodies. Trends Cell Biol 23:118-28
Chen, Chun-Ting; Hehnly, Heidi; Doxsey, Stephen J (2012) Orchestrating vesicle transport, ESCRTs and kinase surveillance during abscission. Nat Rev Mol Cell Biol 13:483-8
Hehnly, Heidi; Chen, Chun-Ting; Powers, Christine M et al. (2012) The centrosome regulates the Rab11- dependent recycling endosome pathway at appendages of the mother centriole. Curr Biol 22:1944-50

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