Skin biological responses to urban pollution in an ex vivo model.

The skin epidermis is continuously exposed to external aggressions, including environmental pollution. The cosmetic industry must be able to offer dedicated products to fight the effects of pollutants on the skin. We set up an experimental model that exposed skin explants maintained in culture to a pollutant mixture.

Chromogranin A preferential interaction with Golgi phosphatidic acid induces membrane deformation and contributes to secretory granule biogenesis.

Chromogranin A (CgA) is a key luminal actor of secretory granule biogenesis at the trans-Golgi network (TGN) level but the molecular mechanisms involved remain obscure. Here, we investigated the possibility that CgA acts synergistically with specific membrane lipids to trigger secretory granule formation. We show that CgA preferentially interacts with the anionic glycerophospholipid phosphatidic acid (PA).

Myosin 1b and F-actin are involved in the control of secretory granule biogenesis.

Hormone secretion relies on secretory granules which store hormones in endocrine cells and release them upon cell stimulation. The molecular events leading to hormone sorting and secretory granule formation at the level of the TGN are still elusive. Our proteomic analysis of purified whole secretory granules or secretory granule membranes uncovered their association with the actomyosin components myosin 1b, actin and the actin nucleation complex Arp2/3.