Examinando por Autor "Vena, Rodrigo"

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    Akap350 recruits Eb1 to the spindle poles, ensuring proper spindle orientation and lumen formation in 3d epithelial cell cultures
    (Springer Nature, 2017-11-02) Almada, Evangelina; Tonucci, Facundo Mauro; Hidalgo, Florencia; Ferretti, Anabela Cecilia; Pariani, Alejandro Pedro; Favre, Cristian; Larocca, María Cecilia; Ibarra, Solange; Vena, Rodrigo; Girardini, Javier; Kierbel, Arlinet
    The organization of epithelial cells to form hollow organs with a single lumen requires the accurate three-dimensional arrangement of cell divisions. Mitotic spindle orientation is defined by signaling pathways that provide molecular links between specific spots at the cell cortex and astral microtubules, which have not been fully elucidated. AKAP350 is a centrosomal/Golgi scaffold protein, implicated in the regulation of microtubule dynamics. Using 3D epithelial cell cultures, we found that cells with decreased AKAP350 expression (AKAP350KD) formed polarized cysts with abnormal lumen morphology. Analysis of mitotic cells in AKAP350KD cysts indicated defective spindle alignment. We established that AKAP350 interacts with EB1, a microtubule associated protein that regulates spindle orientation, at the spindle poles. Decrease of AKAP350 expression lead to a significant reduction of EB1 levels at spindle poles and astral microtubules. Conversely, overexpression of EB1 rescued the defective spindle orientation induced by deficient AKAP350 expression. The specific delocalization of the AKAP350/EB1complex from the centrosome decreased EB1 levels at astral microtubules and lead to the formation of 3D-organotypic structures which resembled AKAP350KD cysts. We conclude that AKAP350 recruits EB1 to the spindle poles, ensuring EB1 presence at astral microtubules and proper spindle orientation during epithelial morphogenesis.
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    Microtubules regulate brush border formation
    (Wiley, 2017-11-06) Tonucci, Facundo Mauro; Ferretti, Anabela Cecilia; Almada, Evangelina; Cribb, Pamela; Vena, Rodrigo; Hidalgo, Florencia; Favre, Cristian; Tyska, Matt J.; Kaverina, Irina; Larocca, María Cecilia; https://orcid.org/0000-0002-6967-5431
    Most epithelial cells contain apical membrane structures associated to bundles of actin filaments, which constitute the brush border. Whereas microtubule participation in the maintenance of the brush border identity has been characterized, their contribution to de novo microvilli organization remained elusive. Hereby, using a cell model of individual enterocyte polarization, we found that nocodazole induced microtubule depolymerization prevented the de novo brush border formation. Microtubule participation in brush border actin organization was confirmed in polarized kidney tubule MDCK cells. We also found that centrosome, but not Golgi derived microtubules, were essential for the initial stages of brush border development. During this process, microtubule plus ends acquired an early asymmetric orientation toward the apical membrane, which clearly differs from their predominant basal orientation in mature epithelia. In addition, overexpression of the microtubule plus ends associated protein CLIP170, which regulate actin nucleation in different cell contexts, facilitated brush border formation. In combination, the present results support the participation of centrosomal microtubule plus ends in the activation of the polarized actin organization associated to brush border formation, unveiling a novel mechanism of microtubule regulation of epithelial polarity.