Role of copine-1 and copine-3 in the epithelial cell response to pneumolysin-induced plasma membrane damage

• Autor(a) principal: Gonçalves, Alexandre David de Amorim
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/35791
• topic: Plasma membrane integrity; Pore-forming toxins; Copine; Cell permeabilization; Intoxication; Streptococcus pneumoniae; Pneumolysin

The establishment of the plasma membrane was essential in the development of Life and evolution, it acts as the first protective barrier of cells. Due to its crucial importance to ensure cell survival, human bacterial pathogens produce poreforming toxins able to permeabilize the plasma membrane, forming stable protein pores. The formation of the pores alters the membrane permeability allowing uncontrolled exchanges of ions, such as calcium and potassium, and small molecules between the intracellular and extracellular milieus, which can ultimately lead to cell death. Cells have, thus, developed several repair mechanisms to overcome the damage, and promote cell survival. One of these repair mechanisms relies on the release of extracellular vesicles that extrude the pores from the cell surface. Proteomic analysis of vesicles released by intoxicated cells revealed the enrichment of copine-1 and copine-3, and raised the hypothesis that these proteins are potentially involved in the repair of plasma membrane damage. Copine-1 and copine-3 are cytoplasmic calcium-responsive proteins able to translocate to the plasma membrane in response to an increase in intracellular calcium levels. Experimental evidence points out that copine-1 and copine-3 have a role in the repair of toxin-induced damage. Here we aimed to assess the role of these proteins in response to bacterial pore-forming toxins, such as pneumolysin, by two complementary approaches: evaluating the ability of cells depleted for the expression of copine-1 or copine-3 to recover their plasma membrane integrity upon intoxication and assessing the intracellular localization of copine-1 and copine- 3 in intoxicated cells. We found that cells that do not express copine-1 or copine-3 are not able to repair plasma membrane damage induced by toxins and do not recover their plasma membrane integrity. Copine-1 and copine-3 are thus essential for the recovery of membrane integrity after intoxication. We also observed that, upon intoxication, copine-1 or copine-3 are specifically recruited to the cortex of the cell, where it accumulates with already characterized repair machinery. Further assays should be performed to uncover the molecular role and the interaction partners of copine-1 and copine-3 in the repair of plasma membrane damage.