The giardial epsin-like protein possess a dual epsin-epsinR role in clathrin-mediated trafficking

FELIZIANI, C; ZAMPONI N,; GOTTIG N; ROPOLO A S; LANFREDI-RANGEL; TOUZ MC

Rosario

Congreso; L Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

Theepsin N-terminal homology (ENTH) domain is an evolutionarily conserved protein module that defines monomeric adaptor proteins of theepsin family. It is present in the epsinor epsin-related (epsinR) proteins, which are implicated in the endocytosis andGolgi-to-endosomes protein trafficking, respectively, in other eukaryoticcells. In Giardia we found a single gene encodinga protein containing an ENTH domain (GlENTHp for G. lamblia ENTH protein), which localized in the cytosol and, like epsin, was associated with αAP-2, clathrin, ubiquitin, interactedwith PI3,4,5P3, and was involved in receptor-mediatedendocytosis. This protein also bonded γAP-1, PI4P, and was implicated inER-to-PV trafficking, like epsinR proteins. Alteration of the GlENTHp functionaffected trophozoite growth showing an accumulation of dense material in thelysosome-like peripheral vacuoles (PVs), indicating that GlENTHp might be implicated in the maintenance of the PVhomeostasis. When the ENTH proteinfamily was analyzed in an evolutionary context, it was suggested that thesubfamily of epsin proteins was acquired more recently probably by duplicationof the epsinR. In this study, we showed evidence that places GlENTHp at thebeginning of the whole family, summarizing the function of epsin and epsinR andsuggesting that GlENTHp might be the epsinR adaptor from which all the familyevolves