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Structural basis of phosphatidylcholine recognition by the C2-domain of cytosolic phospholipase A₂α.

ABSTRACT: Ca²⁺-stimulated translocation of cytosolic phospholipase A₂α (cPLA₂α) to the Golgi induces arachidonic acid production, the rate-limiting step in pro-inflammatory eicosanoid synthesis. Structural insights into the cPLA₂α preference for phosphatidylcholine (PC)-enriched membranes have remained elusive. Here, we report the structure of the cPLA₂α C2-domain (at 2.2 Å resolution), which contains bound 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) and Ca²⁺ ions. Two Ca²⁺ are complexed at previously reported locations in the lipid-free C2-domain. One of these Ca²⁺ions, along with a third Ca²⁺, bridges the C2-domain to the DHPC phosphate group, which also interacts with Asn65. Tyr96 plays a key role in lipid headgroup recognition via cation-π interaction with the PC trimethylammonium group. Mutagenesis analyses confirm that Tyr96 and Asn65 function in PC binding selectivity by the C2-domain and in the regulation of cPLA₂α activity. The DHPC-binding mode of the cPLA₂α C2-domain, which differs from phosphatidylserine or phosphatidylinositol 4,5-bisphosphate binding by other C2-domains, expands and deepens knowledge of the lipid-binding mechanisms mediated by C2-domains.

SUBMITTER: Hirano Y

PROVIDER: S-EPMC6550875 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:This study was conducted to test the hypothesis that the CYP1B1 (cytochrome P450 1B1)-testosterone metabolite 6β-hydroxytestosterone contributes to angiotensin II-induced hypertension by promoting activation of group IV cPLA2α (cytosolic phospholipase A2α) and generation of prohypertensive eicosanoids in male mice. Eight-week-old male intact or orchidectomized cPLA2α+/+/Cyp1b1+/+ and cPLA2α-/-/Cyp1b1+/+ and intact cPLA2α+/+/Cyp1b1-/- mice were infused with angiotensin II (700 ng/kg/min, subcutaneous) for 2 weeks and injected with 6β-hydroxytestosterone (15 μg/g/every third day, intraperitoneal). Systolic blood pressure was measured by tail-cuff and confirmed by radiotelemetry. Angiotensin II-induced increase in systolic blood pressure, cardiac and renal collagen deposition, and reactive oxygen species production were reduced by disruption of the cPLA2α or Cyp1b1 genes or by administration of the arachidonic acid metabolism inhibitor 5,8,11,14-eicosatetraynoic acid to cPLA2α+/+/Cyp1b1+/+ mice. 6β-hydroxytestosterone treatment restored these effects of angiotensin II in cPLA2α+/+/Cyp1b1-/- mice but not in orchidectomized cPLA2α-/-/Cyp1b1+/+ mice, which were lowered by 5,8,11,14-eicosatetraynoic acid in cPLA2α+/+/Cyp1b1-/- mice. Antagonists of prostaglandin E2-EP1/EP3 receptors and thromboxane A2-TP receptors decreased the effect of 6β-hydroxytestosterone in restoring the angiotensin II-induced increase in systolic blood pressure, cardiac and renal collagen deposition, and reactive oxygen species production in cPLA2α+/+/Cyp1b1-/- mice. These data suggest that 6β-hydroxytestosterone promotes angiotensin II-induced increase in systolic blood pressure and associated pathogenesis via cPLA2α activation and generation of eicosanoids, most likely prostaglandin E2 and thromboxane A2 that exerts prohypertensive effects by stimulating EP1/EP3 and TP receptors, respectively. Therefore, agents that selectively block these receptors could be useful in treating testosterone exacerbated angiotensin II-induced hypertension and its pathogenesis.

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Structural basis of phosphatidylcholine recognition by the C2-domain of cytosolic phospholipase A₂α.

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Dataset Information

Structural basis of phosphatidylcholine recognition by the C2-domain of cytosolic phospholipase A2α.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

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Structural basis of phosphatidylcholine recognition by the C2-domain of cytosolic phospholipase A₂α.