Fig. 5
From: ACE2 in chronic disease and COVID-19: gene regulation and post-translational modification
Upregulation of ACE2 by SARS-CoV-2-induced GLK (MAP4K3) in epithelial cells. Spike protein of SARS-CoV-2 induces GLK (MAP4K3) mRNA levels in lung epithelial cells. GLK enhances ACE2 stability by phosphorylating ACE2 at Ser776 and Ser783 residues, leading to dissociation of ACE2 and the E3 ubiquitin ligase UBR4. Moreover, SARS-CoV-2-induced GLK increases epithelial cell-derived exosomes, resulting in an induction of exosomal ACE2. ACE2 proteins are transported by epithelial cell-derived exosomes to other epithelial cells, inducing cell susceptibility to SARS-CoV-2 virus