Cell Biology of the Endoplasmic Reticulum and the Golgi Apparatus through Proteomics

Enriched endoplasmicreticulum(ER) and Golgimembranes subjected tomass spectrometry have uncovered overa thousand different proteins assigned to the ER and Golgi apparatus of rat liver. This, in turn, led to the uncovering of several hundred proteins of poorly understood function and, through hierarchical clustering, showed that proteins distributed in patterns suggestive of microdomains in cognate organelles. This has led to new insights with respect to theirintracellular localization and function.Anotheroutcomehas beenthe critical testing ofthecisternalmaturationhypothesisshowingoverwhelmingsupportforapredominantrole of COPI vesicles in the transport of resident proteins of the ER and Golgi apparatus (as opposed to biosynthetic cargo). Here we will discuss new insights gained and also highlight newavenuesundertaken tofurtherexplorethe cellbiologyofthe ERandthe Golgiapparatus through tandem mass spectrometry.