Sequences in the cytoplasmic tail of SARS-CoV-2 Spike facilitate expression at the cell surface and syncytia formation

• Published in: Nature communications Vol. 12; no. 1; p. 5333
• Main Authors: Cattin-Ortolá, Jérôme, Welch, Lawrence G., Maslen, Sarah L., Papa, Guido, James, Leo C., Munro, Sean
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09.09.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 14/19; 631/1647/296; 631/250/590/2293; 631/326/596/2557; 631/326/596/4130; 631/80/313/1525; 82/58; ACE2; Actin; Angiotensin-converting enzyme 2; Angiotensin-Converting Enzyme 2 - metabolism; Animals; Autophagy; Binding sites; Cell fusion; Cell Membrane - metabolism; Cell surface; Chlorocebus aethiops; COP-Coated Vesicles - metabolism; COVID-19 - metabolism; Domains; Endoplasmic reticulum; Endoplasmic Reticulum - metabolism; Expression vectors; Giant Cells - metabolism; Golgi apparatus; Golgi Apparatus - metabolism; HEK293 Cells; Histidine; Humanities and Social Sciences; Humans; Life cycle analysis; mRNA; multidisciplinary; Phagocytosis; Protein Binding; Protein Domains; Proteins; Proteomics; SARS-CoV-2 - metabolism; Science; Science (multidisciplinary); Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Spike Glycoprotein, Coronavirus - metabolism; Spike protein; Syncytia; Vaccines; Vero Cells; Viral diseases; Virus Assembly - genetics
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-25589-1

The Spike (S) protein of SARS-CoV-2 binds ACE2 to direct fusion with host cells. S comprises a large external domain, a transmembrane domain, and a short cytoplasmic tail. Understanding the intracellular trafficking of S is relevant to SARS-CoV-2 infection, and to vaccines expressing full-length S from mRNA or adenovirus vectors. Here we report a proteomic screen for cellular factors that interact with the cytoplasmic tail of S. We confirm interactions with the COPI and COPII vesicle coats, ERM family actin regulators, and the WIPI3 autophagy component. The COPII binding site promotes exit from the endoplasmic reticulum, and although binding to COPI should retain S in the early Golgi where viral budding occurs, there is a suboptimal histidine residue in the recognition motif. As a result, S leaks to the surface where it accumulates and can direct the formation of multinucleate syncytia. Thus, the trafficking signals in the tail of S indicate that syncytia play a role in the SARS-CoV-2 lifecycle. The Spike protein of SARS-CoV-2 has a C-terminal cytoplasmic tail. Here the authors show that this tail binds trafficking machinery via sequences that appear optimised to ensure that Spike accumulates at the site of viral budding in the Golgi but that some can also traffic to the cell surface to induce syncytia formation.