In eukaryotic cells, protein sorting is a highly regulated mechanism important for many physiological events. After synthesis in the endoplasmic reticulum and trafficking to the Golgi apparatus, proteins sort to many different cellular destinations including the endolysosomal system and the extracellular space. Secreted proteins need to be delivered directly to the cell surface. Sorting of secreted proteins from the Golgi apparatus has been a topic of interest for over thirty years, yet there is still no clear understanding of the machinery that forms the post-Golgi carriers. Most evidence points to these post-Golgi carriers being tubular pleomorphic structures that bud from the trans-face of the Golgi. In this review, we present the background studies and highlight the key components of this pathway, we then discuss the machinery implicated in the formation of these carriers, their translocation across the cytosol, and their fusion at the plasma membrane.
Keywords: ATP, adenosine triphosphate; BFA, Brefeldin A; CARTS, CARriers of the TGN to the cell Surface; CI-MPR, cation-independent mannose-6 phosphate receptor; Constitutive Secretion; CtBP3/BARS, C-terminus binding protein 3/BFA adenosine diphosphate–ribosylated substrate; ER, endoplasmic reticulum; GPI-anchored proteins, glycosylphosphatidylinositol-anchored proteins; GlcCer, glucosylceramidetol; Golgi to plasma membrane sorting; PAUF, pancreatic adenocarcinoma up-regulated factor; PKD, Protein Kinase D; RUSH, retention using selective hooks; SBP, streptavidin-binding peptide; SM, sphingomyelin; SNARE, soluble N-ethylmaleimide sensitive fusion protein attachment protein receptor; SPCA1, secretory pathway calcium ATPase 1; Secretion; TGN, trans-Golgi Network; TIRF, total internal reflection fluorescence; VSV, vesicular stomatitis virus; pleomorphic tubular carriers; post-Golgi carriers; ts, temperature sensitive.
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