Actin nucleation at the centrosome controls lymphocyte polarity.

Dorian Obino (1) , Francesca Farina (2) , Odile Malbec (1) , Pablo J Sáez (1) , Mathieu Maurin (1) , Jérémie Gaillard (2) , Florent Dingli (3) , Damarys Loew (3) , Alexis Gautreau (4) , Maria-Isabel Yuseff (5) , Laurent Blanchoin (2) , Manuel Théry (2) , Ana-Maria Lennon-Duménil (1)

1 U932 - Immunité et cancer
2 LPCV - Laboratoire de physiologie cellulaire végétale
3 Laboratoire de Spectrométrie de Masse Protéomique
4 BIOC - Laboratoire de Biochimie de l'Ecole polytechnique
5 UC - Pontificia Universidad Católica de Chile

Cell polarity is required for the functional specialization of many cell types including lymphocytes. A hallmark of cell polarity is the reorientation of the centrosome that allows repositioning of organelles and vesicles in an asymmetric fashion. The mechanisms underlying centrosome polarization are not fully understood. Here we found that in resting lymphocytes, centrosome-associated Arp2/3 locally nucleates F-actin, which is needed for centrosome tethering to the nucleus via the LINC complex. Upon lymphocyte activation, Arp2/3 is partially depleted from the centrosome as a result of its recruitment to the immune synapse. This leads to a reduction in F-actin nucleation at the centrosome and thereby allows its detachment from the nucleus and polarization to the synapse. Therefore, F-actin nucleation at the centrosome-regulated by the availability of the Arp2/3 complex-determines its capacity to polarize in response to external stimuli.

Mots clés: cell migration; cell division; cell polarity; centrosome polarization; actin nucleation; actin associated protein; Arp2/3; Centrosome associated protein

Domaines: Biologie cellulaire

Dorian Obino, Francesca Farina, Odile Malbec, Pablo J Sáez, Mathieu Maurin, et al.. Actin nucleation at the centrosome controls lymphocyte polarity.. Nature Communications, 2015, 7, pp.10969. ⟨10.1038/ncomms10969⟩. ⟨hal-01331141⟩