Diversity in the Accessory Proteins of SARS-CoV-2, SARS-CoV, and MERS-CoV Betacoronaviruses

Along with structural and non-structural proteins, SARS-CoV-2, SARS-CoV, and MERS-CoV can also express accessory proteins. During the past few years, there have been only a few studies focusing on this set of proteins. Despite available data on these proteins, there are still a lot of questions on the functions of these proteins during infection that must be answered. With these three betacoronaviruses causing outbreaks in humans during the past few years, the need for a thorough understanding of the roles of these proteins is becoming more important and relevant. This review provides a survey of the existing knowledge on the roles of these proteins during infection. In addition to current evidence, a more comprehensive view of the functions of these proteins is presented together with their potential as therapeutic targets, which were determined by using different bioinformatics platforms. This information may help test effective therapeutic regimens against these viruses and in preparing for future pandemics.