Chemoproteomic Discovery of AADACL1 as a Regulator of Human Platelet Activation

• Application of activity-based protein profiling to platelets and thrombosis
• An endogenous target of the carbamate WWL91 is AADACL1 in platelets
• AADACL1 regulates αIIbβ3 integrin activation and thrombus formation in platelets
• AADACL1 deacetylates an ether lipid that blocks platelet signaling and aggregation

SummaryA comprehensive knowledge of the platelet proteome is necessary for understanding thrombosis and for envisioning antiplatelet therapies. To discover other biochemical pathways in human platelets, we screened platelets with a carbamate library designed to interrogate the serine hydrolase subproteome and used competitive activity-based protein profiling to map the targets of active carbamates. We identified an inhibitor that targets arylacetamide deacetylase-like 1 (AADACL1), a lipid deacetylase originally identified in invasive cancers. Using this compound, along with highly selective second-generation inhibitors of AADACL1, metabolomics, and RNA interference, we show that AADACL1 regulates platelet aggregation, thrombus growth, RAP1 and PKC activation, lipid metabolism, and fibrinogen binding to platelets and megakaryocytes. These data provide evidence that AADACL1 regulates platelet and megakaryocyte activation and highlight the value of this chemoproteomic strategy for target discovery in platelets.

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