Membrane surface recognition by the ASAP1 PH domain and consequences for interactions with the small GTPase Arf1.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32998886.
- Also identified by DOI 10.1126/sciadv.abd1882 and PMC identifier 7527224.
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Abstract
Adenosine diphosphate-ribosylation factor (Arf) guanosine triphosphatase-activating proteins (GAPs) are enzymes that need to bind to membranes to catalyze the hydrolysis of guanosine triphosphate (GTP) bound to the small GTP-binding protein Arf. Binding of the pleckstrin homology (PH) domain of the ArfGAP With SH3 domain, ankyrin repeat and PH domain 1 (ASAP1) to membranes containing phosphatidylinositol 4,5-bisphosphate [PI(4,5)P<sub>2</sub>] is key for maximum GTP hydrolysis but not fully understood. By combining nuclear magnetic resonance, neutron reflectometry, and molecular dynamics simulation, we show that binding of multiple PI(4,5)P<sub>2</sub> molecules to the ASAP1 PH domain (i) triggers a functionally relevant allosteric conformational switch and (ii) maintains the PH domain in a well-defined orientation, allowing critical contacts with an Arf1 mimic to occur. Our model provides a framework to understand how binding of the ASAP1 PH domain to PI(4,5)P<sub>2</sub> at the membrane may play a role in the regulation of ASAP1.