title: Cep192 controls the balance of centrosome and non-centrosomal microtubules during interphase.
abstract: Cep192 is a centrosomal protein that contributes to the formation and function of the mitotic spindle in mammalian cells. Cep192's mitotic activities stem largely from its role in the recruitment to the centrosome of numerous additional proteins such as gamma-tubulin and Pericentrin. Here, we examine Cep192's function in interphase cells. Our data indicate that, as in mitosis, Cep192 stimulates the nucleation of centrosomal microtubules thereby regulating the morphology of interphase microtubule arrays. Interestingly, however, cells lacking Cep192 remain capable of generating normal levels of MTs as the loss of centrosomal microtubules is augmented by MT nucleation from other sites, most notably the Golgi apparatus. The depletion of Cep192 results in a significant decrease in the level of centrosome-associated gamma-tubulin, likely explaining its impact on centrosome microtubule nucleation. However, in stark contrast to mitosis, Cep192 appears to maintain an antagonistic relationship with Pericentrin at interphase centrosomes. Interphase cells depleted of Cep192 display significantly higher levels of centrosome-associated Pericentrin while overexpression of Cep192 reduces the levels of centrosomal Pericentrin. Conversely, depletion of Pericentrin results in elevated levels of centrosomal Cep192 and enhances microtubule nucleation at centrosomes, at least during interphase. Finally, we show that depletion of Cep192 negatively impacts cell motility and alters normal cell polarization. Our current working hypothesis is that the microtubule nucleating capacity of the interphase centrosome is determined by an antagonistic balance of Cep192, which promotes nucleation, and Pericentrin, which inhibits nucleation. This in turn determines the relative abundance of centrosomal and non-centrosomal microtubules that tune cell movement and shape.
authors: Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, United States of America.
authors: Brian P
authors: BP
authors: O'Rourke
authors: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors: Maria Ana
authors: MA
authors: Gomez-Ferreria
authors: Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, United States of America.
authors: Robin H
authors: RH
authors: Berk
authors: Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, United States of America.
authors: Alexandra M U
authors: AM
authors: Hackl
authors: Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America.
authors: Matthew P
authors: MP
authors: Nicholas
authors: Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, United States of America.
authors: Sean C
authors: SC
authors: O'Rourke
authors: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors: Laurence
authors: L
authors: Pelletier
authors: Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, United States of America.
authors: David J
authors: DJ
authors: Sharp
mesh_terms: D000941:Antigens / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement; D016764:Cell Polarity; D018385:Centrosome / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007399:Interphase; D008870:Microtubules / Q000378:metabolism*
chemical_list: D000941:Antigens; C526596:Cep192 protein, human; D002868:Chromosomal Proteins, Non-Histone; C086178:pericentrin