Séminaire de l’Institut Jacques Monod – Frédéric Pincet
23 mai 2025 - 11 h 45 min - 13 h 00 min
Invité par l’équipe Romet-Lemonne/Jégou, Frédéric Pincet (CNRS/ENS-PLS, Paris) présentera un séminaire de l’Institut Jacques Monod sur le thème :
The Dual Role of Golgins in Maintaining Golgi Structure and Mediating Vesicle Traffic
Résumé :
The architecture of the Golgi apparatus is remarkably complex. In mammalian cells, it is composed of stacks of disk-shaped membrane compartments that are laterally connected to form a ribbon-like structure. These stacks are polarized along the cis-to-trans axis and are embedded within a dense protein matrix, whose primary components belong to the Golgin protein family. This refined organization is transiently lost during mitosis, when the Golgi apparatus disperses into small vesicular and tubular remnants. However, during telophase, these remnants rapidly reassemble within minutes, restoring the original architecture and cisternal composition. Even during interphase, the integrity of the Golgi architecture is continuously challenged by dynamic processes, including intensive vesicular trafficking both within the Golgi and with neighboring compartments, as well as by cisternal maturation. As a result, the Golgi apparatus presents a seemingly paradoxical combination of dynamic plasticity and structural robustness. In this seminar, I will propose that Golgins act as key regulators balancing this duality. Golgins can function both as vesicle tethers, facilitating trafficking, and as structural scaffolds, promoting the spontaneous organization of the Golgi matrix. We tested this hypothesis using a combination of in vitro biophysical and biochemical assays, as well as super-resolution imaging of Golgin localization. Our results show that Golgins can self-assemble into two-dimensional condensates exhibiting a hierarchical set of interactions correlated with Golgi organization. Simultaneously, Golgins and their condensates are capable of specifically tethering vesicles, thus maintaining efficient vesicular trafficking within the matrix.