Cardiolipin Regulates the Activity of the Mitochondrial ABC Transporter ABCB10

Biochemistry. 2023 Nov 7;62(21):3159-3165. doi: 10.1021/acs.biochem.3c00417. Epub 2023 Oct 9.

Abstract

The ATP-binding cassette (ABC) transporter ABCB10 resides in the inner membrane of mitochondria and is implicated in erythropoiesis. Mitochondria from different cell types share some specific characteristics, one of which is the high abundance of cardiolipin. Although previous studies have provided insight into ABCB10, the affinity and selectivity of this transporter toward lipids, particularly those found in the mitochondria, remain poorly understood. Here, native mass spectrometry is used to directly monitor the binding events of lipids to human ABCB10. The results reveal that ABCB10 binds avidly to cardiolipin with an affinity significantly higher than that of other phospholipids. The first three binding events of cardiolipin display positive cooperativity, which is suggestive of specific cardiolipin-binding sites on ABCB10. Phosphatidic acid is the second-best binder of the lipids investigated. The bulk lipids, phosphatidylcholine and phosphatidylethanolamine, display the weakest binding affinity for ABCB10. Other lipids bind ABCB10 with a similar affinity. Functional assays show that cardiolipin regulates the ATPase activity of ABCB10 in a dose-dependent fashion. ATPase activity of ABCB10 was also impacted in the presence of other lipids but to a lesser extent than cardiolipin. Taken together, ABCB10 has a high binding affinity for cardiolipin, and this lipid also regulates the ATPase activity of the transporter.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • ATP-Binding Cassette Transporters* / chemistry
  • Adenosine Triphosphatases / metabolism
  • Cardiolipins* / metabolism
  • Humans
  • Membrane Transport Proteins / metabolism
  • Mitochondria / metabolism

Substances

  • ATP-Binding Cassette Transporters
  • Cardiolipins
  • Membrane Transport Proteins
  • Adenosine Triphosphatases
  • ABCB10 protein, human