ABSTRACT
The membrane (M) glycoprotein of coronaviruses (CoVs) serves as the nidus for virion assembly. Using a yeast two‐hybrid screen, we identified the interaction of the cytosolic tail of Murine Hepatitis Virus (MHV‐CoV) M protein with Myosin Vb (MYO5B) (Figure 1A). MHV‐CoV M interacts specifically with the alternative splice variant of cellular MYO5B including Exon D (MYO5B+D), that also mediates interaction with cellular Rab10. When co‐expressed in human lung epithelial A549 and canine kidney epithelial MDCK cells, MYO5B+D co‐localized with MHV‐CoV M protein, as well as with M proteins from porcine epidemic diarrhea Virus (PEDV‐CoV), Middle East Respiratory Syndrome (MERS‐CoV) and Severe Acute Respiratory Syndrome 2 (SARS‐CoV‐2) (Figure 2). M‐GFP chimeric proteins co‐expressed with mCherry‐MYO5B+D also co‐localized with endogenous Rab10 and Rab11a (Figure 1B,C). We identified point mutations in MHV‐CoV M that blocked the interaction with MYO5B+D in yeast 2‐hybrid assays (Figure 1B). One of these point mutations (E121K) was previously shown to block MHV‐CoV virion assembly, and it blocked interaction with MYO5B+D. The E to K mutation at homologous positions in PEDV‐CoV, MERS‐CoV and SARS‐CoV‐2 M proteins also blocked colocalization with MYO5B+D. Knockdown of Rab10 blocked the co‐localization of the M proteins with MYO5B+D (Figure 2). Re‐expression of Cerulein‐Rab10 in Rab10 KD cells re‐established colocalization between M proteins and MYO5B+D (Figure 2). Our results suggest that the interaction of CoV M proteins with MYO5B+D may play a role in regulating their trafficking through Rab10‐containing membrane systems in epithelial cells.