Responsable: Manuel Muñiz Guinea
Tipo de Proyecto/Ayuda: Plan Nacional del 2002
Referencia: BMC2002-03133
Fecha de Inicio: 01-12-2002
Fecha de Finalización: 01-12-2005

Empresa/Organismo financiador/es:

• Ministerio de Ciencia y Tecnología

Equipo:

• Investigadores:
  • Ángel Velasco López

Resumen del proyecto:

Vesicle-mediated retrograde transport from the Golgi complex to the endoplasmic reticulum (ER) is crucial for eukaryotic cell physiology. It allows efficient intracellular retention of endogenous ER components while preventing misfolded proteins escaped to the Golgi from moving forward along the secretory pathway. p24 transmembrane protein family is present in different organisms from yeast to mammals in a highly conserved form. It is generally believed that p24 proteins are assembled into a heteromeric complex that continuously cycles between ER and the Golgi. Cells expressing several p24 mutated forms are unable to retain intracellularly both ER residents and misfolded secretory proteins and, therefore, it is assumed a key role for these proteins in Golgi-ER retrograde transport. However, this has not been proved conclusively so far. The aim of this proposal is to analyse the role played by p24 proteins in the retrieval of these molecules using the yeast Saccharomyces cerevisiae as a cell-model system. We will begin by setting up an in vitro cell-free system designed to purify and analyse the molecular composition of Golgi-derived retrograde transport vesicles. Along with other techniques this will allow to address these points: 1) The p24 requirement for sorting and inclusion into vesicles of both receptors (Erd2p, Rer1p) and membrane cargo proteins, 2) Identification of the p24 domains which are relevant for retrograde transport, 3) Functional analysis of p24 interactions with components of the vesicular transport machinery, and 4) To evaluate a possible role of p24 proteins as receptors of misfolded and unassembled proteins. It is our hope that this study will allow us to better understand the operation of quality controls taking place at the early secretory pathway.