MLKL and COVID-19: The prominent role of this process in SARS-CoV-2 infection has been confirmed in vitro, where the phosphorylation of mixed lineage kinase domain like pseudokinase (MLKL), a key necroptosis protein, was studied in Calu-3 human lung cancer cells, and clinical investigations showed that patients with severe COVID-19 display upregulation of RIPK3 proteins that trigger necroptosis signalling [140].