Because of the COVID-19 pandemic, the novel coronavirus SARS-CoV-2 has risen to shape
scientific research during 2020, with its spike (S) protein being a predominant focus. The S
protein is likely the most complicated of all viral glycoproteins and is a key factor in
immunological responses and virus pathogenesis. It is also the driving force dictating virus
entry mechanisms, which are highly “plastic” for coronaviruses, allowing a plethora of
options for different virus variants and strains in different cell types. Here we review …