Phagocytosis depends on reorganization of cortical actin coordinated with the recruitment of intracellular compartments, which fuse with the plasma membrane, a process necessary to for actin dynamics and efficient particle internalization (Niedergang and Grinstein, 2018). We showed that mDia1, an actin nucleator of the formin family, is required downstream of the CR3 integrin receptors and highlighted an original dialogue between the microtubules and actin (Colucci-Guyon et al., 2005; Lewkowicz et al., 2008). We revealed recently that the negative Arp2/3 regulator Arpin is required for efficient phagosome formation (Jubrail et al., 2020).  We identified the B cell lymphoma/leukemia-10 (Bcl10) protein, as unexpectedly involved in actin dynamics by controlling trafficking and signaling during phagocytosis (Marion et al., 2012). We developed an original method based on evanescent wave microscopy to monitor the spatiotemporal location of molecular players in nascent phagosomes in three dimensions (Marie-Anais et al., 2016a), which allowed us to identify that dynamin2 is crucial to control phagosome formation and closure (Marie-Anais et al., 2016b; Mularski et al., 2021).

We now study in details early steps of phagocytic receptors clustering and force generation (Mularski and Niedergang, 2019), taking advantage of unique deformable lipid droplets, in collaboration with Jacques Fattaccioli (Laboratoire microfluidique Institut Pierre Gilles de Gennes – CNRS, ENS, Sorbonne Université) and Jean-Maurice MALLET (Laboratoire des Biomolécules, CNRS, ENS, Sorbonne Université) in the context of a CNRS 80 PRIME programme and ANR PhagoChemiForce. We also analyze the fate of ingested materials leading to their degradation.