%0 Journal Article
%T Intra-Golgi Transport: Roles for Vesicles, Tubules, and Cisternae
%A Jos¨¦ A. Mart¨ªnez-Men¨¢rguez
%J ISRN Cell Biology
%D 2013
%R 10.1155/2013/126731
%X The Golgi complex is considered the central station of the secretory pathway where cargo proteins and lipids are properly modified, classified, packed into specific carriers and delivered to their final destinations. Early electron microscope studies showed the extraordinary structural complexity of this organelle. However, despite the large volume of incoming and outgoing traffic, it is able to maintain its architecture, although it is also flexible enough to adapt to the functional status of the cell. Many components of the molecular machinery involved in membrane traffic and other Golgi functions have been identified. However, some basic aspects of Golgi functioning remain unsolved. For instance, how cargo moves through the stack remains controversial and two classical models have been proposed: vesicular transport and cisternal maturation. Since neither of these models explains all the experimental data, a combination of these models as well as new models have been proposed. In this context, the specific role of the cisternae, vesicles and tubules needs to be clarified. In this review, we summarize our current knowledge of the Golgi organization and function, focusing on the mechanisms of intra-Golgi transport. 1. Introduction Eukaryotic cells are highly compartmentalized in organelles, which are surrounded by membranes. Every compartment has its own composition, structure, and function. However, these elements are not totally isolated because there is a continuous flow of components between them. Endocytic and secretory routes are complex processes involving formation, movement, and fusion with the specific targets of transport carriers. Palade was a pioneer in this field by establishing that newly synthesized proteins in the endoplasmic reticulum (ER) move to the Golgi complex (GC) and they are packed in secretory granules before being secreted [1]. Although this concept is a dogma in cell biology, some proteins bypass the GC on their way to the cell surface, a process known as unconventional trafficking [2]. The central role of the GC in the secretory pathway is nowadays understood [3, 4]. The GC receives newly synthesized proteins and lipids from the ER. This cargo is classified, packed, and delivered to the final destination, but is extensively modified on the way, mainly involving the glycosylation of proteins and lipids. Recently, a key role in many cellular processes has been associated with this compartment including microtubule nucleation, signaling, and calcium homoeostasis [5]. In recent decades the molecular machinery involved in many
%U http://www.hindawi.com/journals/isrn.cell.biology/2013/126731/