Proteins bound for the cell surface, lysosomes and secretory storage granules share a common pathway of intracellular transport. After their synthesis and translocation into the endoplasmic reticulum, these proteins traverse the secretory pathway by a series of vesicular transfers. Little is known about the mechanisms by which proteins are translocated, transported with ER, collected into transport vesicles, or how these vesicles form, identify their targets and subsequently fuse with their target membrane. While under normal conditions, an extensive flow of proteins and lipids is sustained, in presence of ethanol the transport is arrested and mucin precursors accumulate in endoplasmic reticulum. To understand the biochemical mechanisms fundamental to exocytosis and to ethanol-induced impairments in the transport, a number of processes required to take place in ordered sequence to facilitate the flow will be evaluated. Effect of ethanol on mucin translocation, early processing, vesicles formation, budding and mucin delivery to Gogi cisternae will be investigated. Vectorial transport of mucin from ER to Golgi will be evaluated in semi-intact cells with preserved organelle integrity and an option to manipulate their cytoplasmic content. Experiments will be conducted to evaluate if ethanol can arrest generation of transport vesicles and whether the transient vesicular coat reflects intermittent association of cytidyltransferase with those membranes. It is hoped that these studies will provide information on the role of glycoprotein processing and lipids synthesis in exocytic pathway and be of value in attempts to ameliorate some of the gastrointestinal consequences associated with alcohol abuse.
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