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L‐lactate dehydrogenase A selectively interacts with phosphatidic acid species containing stearic acid at the sn‐1 position
Author(s) -
HOSHINO FUMI,
SAKANE FUMIO
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.00450
Subject(s) - phosphatidic acid , cardiolipin , phosphatidylserine , lactate dehydrogenase , biochemistry , phosphatidylinositol , chemistry , dehydrogenase , phosphatidylcholine , lactate dehydrogenase a , stearic acid , phospholipid , biology , enzyme , signal transduction , organic chemistry , membrane
Phosphatidic acid (PA) acts as a lipid second messenger and is involved in a wide variety of cellular events. PA consists of various molecular species that have different acyl chains at the sn‐1 and sn‐2 positions, and consequently, mammalian cells contain at least 50 structurally distinct PA species. However, the different roles of each PA species are poorly understood. Results In the present study, we attempted to identify 16:0/16:0‐PA (X:Y = the number of carbon atoms:the number of double bonds)‐binding proteins from the mouse skeletal muscle via a screening method using 16:0/16:0‐PA‐containing liposome precipitation and MS/MS analysis. Intriguingly, we have found for the first time that l ‐lactate dehydrogenase A (LDHA) bound to 16:0/16:0‐PA. LDHA catalyzes conversion of pyruvate to lactate and is considered to be a important checkpoint of anaerobic glycolysis. Moreover, its expression level is elevated in many types of cancers and has been linked to tumor growth, maintenance, and invasion. Further characterization revealed that LDHA specifically bound to PA and did not associate with other phospholipids, such as phosphatidylcholine, phosphatidylserine, phosphatidylglycerol, phosphatidylinositol and cardiolipin. Interestingly, in addition to 16:0/16:0‐PA, PA species containing stearic acid (18:0) at the sn‐1 position, 18:0/18:0‐PA, 18:0/20:4‐PA and 18:0/22:6‐PA, also interacted with LDHA in vitro and their binding activities were significantly stronger than 16:0/16:0‐PA. However, LDHA failed to associate with 16:0/18:1‐PA, 16:0‐lyso phosphatidic acid (LPA) and 18:0‐LPA. We are now examining whether the 18:0‐containing PAs affect the localization and activity of LDHA. Conclusion We demonstrated for the first time that LDHA is a PA‐binding protein. Moreover, we revealed that LDHA is a very unique PA‐binding protein that possesses exceptional preference to PA species containing 18:0 at the sn‐1 position. We have already reported that creatine kinase muscle type and α‐synuclein bound to saturated fatty acid‐ and/or monounsaturated fatty acid‐containing PAs ( e.g. 16:0/16:0‐ and 16:0/18:1‐PA) and monounsaturated fatty acid‐containing PAs ( e.g. 18:1/18:1‐PA), respectively. Taken together, these results indicate that there are many functionally distinct PA‐binding proteins having different selectivities to PA species. Therefore, it is likely that each PA species individually regulate diverse physiological functions through different PA‐binding proteins.