The Characterisation Of Ectodomain Shedding Of Angiotensin Converting Enzyme 2 Ace2

The Characterisation of Ectodomain Shedding of Angiotensin-converting Enzyme 2 (ACE2)

Angiotensin-converting enzyme 2 (ACE2) is the only mammalian homologue of the well-characterised angiotensin-I converting enzyme (ACE). ACE2 shares 40% identity and 60% similarity in overall protein sequence with ACE. Like ACE, ACE2 is a type I integral membrane protein and a zinc dependent metalloprotease. ACE2 has recently been shown to undergo a proteolytic cleavage event, releasing an active soluble ectodomain. This cleavage-event is also commonly known as ectodomain shedding. The studies outlined in this thesis were designed to characterise the regulation of ACE2 ectodomain shedding, specifically looking at the interaction of this carboxypeptidase with calmodulin, potential site of cleavage mediated by tumour necrosis factor-[alpha] converting enzyme (also known as TACE or ADAM17), as well as the mechanism(s) responsible for the activation of this cleavage event. Calmodulin gel shift assays have showed that this calcium regulatory protein is able to bind to both peptides that mimic the cytoplasmic tail of ACE2. Furthermore, we showed that GST-calmodulin fusion proteins were successfully co-immunoprecipitated along with full-length ACE2, in vitro. By using increasing concentrations of the calmodulin specific inhibitor, trifluoroperazine and calmidazolium, we have observed increase in the shedding activity of ACE2 endogenously expressed in Huh-7 cells (n≥3, one-way ANOVA, P

Endocrinology and COVID-19: A cross-disciplinary topic, volume II

Beyond the conventional Renin Angiotensin System