Post-Golgi anterograde transport requires GARP-dependent endosome-to-TGN retrograde transport

• Published in: Molecular biology of the cell Vol. 26; no. 17; pp. 3071 - 3084
• Main Authors: Hirata, Tetsuya, Fujita, Morihisa, Nakamura, Shota, Gotoh, Kazuyoshi, Motooka, Daisuke, Murakami, Yoshiko, Maeda, Yusuke, Kinoshita, Taroh
• Format: Journal Article
• Language: English
• Published: United States The American Society for Cell Biology 01.09.2015
• Subjects: Biological Transport; Cell Culture Techniques; Endosomes - metabolism; Gene Knockout Techniques; Glycosylphosphatidylinositols - metabolism; Golgi Apparatus - metabolism; GPI-Linked Proteins - metabolism; HEK293 Cells; HeLa Cells; Humans; Membrane Proteins - metabolism; Protein Transport; RNA Interference; SNARE Proteins - metabolism; trans-Golgi Network - metabolism; Vesicular Transport Proteins - genetics; Vesicular Transport Proteins - metabolism
• ISSN: 1059-1524; 1939-4586
• DOI: 10.1091/mbc.E14-11-1568

The importance of endosome-to– trans-Golgi network (TGN) retrograde transport in the anterograde transport of proteins is unclear. In this study, genome-wide screening of the factors necessary for efficient anterograde protein transport in human haploid cells identified subunits of the Golgi-associated retrograde protein (GARP) complex, a tethering factor involved in endosome-to-TGN transport. Knockout (KO) of each of the four GARP subunits, VPS51–VPS54, in HEK293 cells caused severely defective anterograde transport of both glycosylphosphatidylinositol (GPI)-anchored and transmembrane proteins from the TGN. Overexpression of VAMP4, v-SNARE, in VPS54-KO cells partially restored not only endosome-to-TGN retrograde transport, but also anterograde transport of both GPI-anchored and transmembrane proteins. Further screening for genes whose overexpression normalized the VPS54-KO phenotype identified TMEM87A, encoding an uncharacterized Golgi-resident membrane protein. Overexpression of TMEM87A or its close homologue TMEM87B in VPS54-KO cells partially restored endosome-to-TGN retrograde transport and anterograde transport. Therefore GARP- and VAMP4-dependent endosome-to-TGN retrograde transport is required for recycling of molecules critical for efficient post-Golgi anterograde transport of cell-surface integral membrane proteins. In addition, TMEM87A and TMEM87B are involved in endosome-to-TGN retrograde transport.