7zpe

Structural highlights

Disease

BCKD_HUMAN Autism-epilepsy syndrome due to branched chain ketoacid dehydrogenase kinase deficiency. The disease is caused by variants affecting the gene represented in this entry. A diet enriched in branched amino acids (BCAAs) allows to normalize plasma BCAA levels. This suggests that it may be possible to treat patients with mutations in BCKDK with BCAA supplementation.

Function

BCKD_HUMAN Serine/threonine-protein kinase component of macronutrients metabolism. Forms a functional kinase and phosphatase pair with PPM1K, serving as a metabolic regulatory node that coordinates branched-chain amino acids (BCAAs) with glucose and lipid metabolism via two distinct phosphoprotein targets: mitochondrial BCKDHA subunit of the branched-chain alpha-ketoacid dehydrogenase (BCKDH) complex and cytosolic ACLY, a lipogenic enzyme of Krebs cycle (PubMed:24449431, PubMed:29779826, PubMed:37558654). Phosphorylates and inactivates mitochondrial BCKDH complex a multisubunit complex consisting of three multimeric components each involved in different steps of BCAA catabolism: E1 composed of BCKDHA and BCKDHB, E2 core composed of DBT monomers, and E3 composed of DLD monomers. Associates with the E2 component of BCKDH complex and phosphorylates BCKDHA on Ser-337, leading to conformational changes that interrupt substrate channeling between E1 and E2 and inactivates the BCKDH complex (PubMed:29779826, PubMed:37558654). Phosphorylates ACLY on Ser-455 in response to changes in cellular carbohydrate abundance such as occurs during fasting to feeding metabolic transition. Refeeding stimulates MLXIPL/ChREBP transcription factor, leading to increased BCKDK to PPM1K expression ratio, phosphorylation and activation of ACLY that ultimately results in the generation of malonyl-CoA and oxaloacetate immediate substrates of de novo lipogenesis and glucogenesis, respectively (PubMed:29779826). Recognizes phosphosites having SxxE/D canonical motif (PubMed:29779826).^{[1] [2] [3]}

References

1. ↑ García-Cazorla A, Oyarzabal A, Fort J, Robles C, Castejón E, Ruiz-Sala P, Bodoy S, Merinero B, Lopez-Sala A, Dopazo J, Nunes V, Ugarte M, Artuch R, Palacín M, Rodríguez-Pombo P, Alcaide P, Navarrete R, Sanz P, Font-Llitjós M, Vilaseca MA, Ormaizabal A, Pristoupilova A, Agulló SB. Two novel mutations in the BCKDK (branched-chain keto-acid dehydrogenase kinase) gene are responsible for a neurobehavioral deficit in two pediatric unrelated patients. Hum Mutat. 2014 Apr;35(4):470-7. PMID:24449431 doi:10.1002/humu.22513
2. ↑ White PJ, McGarrah RW, Grimsrud PA, Tso SC, Yang WH, Haldeman JM, Grenier-Larouche T, An J, Lapworth AL, Astapova I, Hannou SA, George T, Arlotto M, Olson LB, Lai M, Zhang GF, Ilkayeva O, Herman MA, Wynn RM, Chuang DT, Newgard CB. The BCKDH Kinase and Phosphatase Integrate BCAA and Lipid Metabolism via Regulation of ATP-Citrate Lyase. Cell Metab. 2018 Jun 5;27(6):1281-1293.e7. PMID:29779826 doi:10.1016/j.cmet.2018.04.015
3. ↑ Roth Flach RJ, Bollinger E, Reyes AR, Laforest B, Kormos BL, Liu S, Reese MR, Martinez Alsina LA, Buzon L, Zhang Y, Bechle B, Rosado A, Sahasrabudhe PV, Knafels J, Bhattacharya SK, Omoto K, Stansfield JC, Hurley LD, Song L, Luo L, Breitkopf SB, Monetti M, Cunio T, Tierney B, Geoly FJ, Delmore J, Siddall CP, Xue L, Yip KN, Kalgutkar AS, Miller RA, Zhang BB, Filipski KJ. Small molecule branched-chain ketoacid dehydrogenase kinase (BDK) inhibitors with opposing effects on BDK protein levels. Nat Commun. 2023 Aug 9;14(1):4812. PMID:37558654 doi:10.1038/s41467-023-40536-y