Depletion of branched-chain aminotransferase 2 (BCAT2) enzyme impairs myoblast survival and myotube formation

© 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society..

Much is known about the positive effects of branched-chain amino acids (BCAA) in regulating muscle protein metabolism. Comparatively much less is known about the effects of these amino acids and their metabolites in regulating myotube formation. Using cultured myoblasts, we showed that although leucine is required for myotube formation, this requirement is easily met by α-ketoisocaproic acid, the ketoacid of leucine. We then demonstrated increases in the expression of the first two enzymes in the catabolism of the three BCAA, branched-chain amino transferase (BCAT2) and branched-chain α-ketoacid dehydrogenase (BCKD), with ~3× increase in BCKD protein expression (p < .05) during differentiation. Furthermore, depletion of BCAT2 abolished myoblast differentiation, as indicated by reduction in the levels of myosin heavy chain-1, troponin and myogenin. Supplementation of incubation medium with branched-chain α-ketoacids or related metabolites derivable from BCAT2 functions did not rescue the defects. However, co-depletion of BCKD kinase partially rescued the defects. Collectively, our data indicate a requirement for BCAA catabolism during myotube formation and that this requirement for BCAT2 likely goes beyond the need for this enzyme to generate the α-ketoacids of the BCAA.

Medienart:

E-Artikel

Erscheinungsjahr:

2019

Erschienen:

2019

Enthalten in:

Zur Gesamtaufnahme - volume:7

Enthalten in:

Physiological reports - 7(2019), 23 vom: 01. Dez., Seite e14299

Sprache:

Englisch

Beteiligte Personen:

Dhanani, Zameer N [VerfasserIn]
Mann, Gagandeep [VerfasserIn]
Adegoke, Olasunkanmi A J [VerfasserIn]

Links:

Volltext

Themen:

BCAT2
Bcat2 protein, rat
Branched-chain amino acids
Differentiation
EC 2.6.1.-
EC 2.6.1.42
EC 3.6.4.1
Journal Article
Metabolism
Mitochondrial Proteins
Myogenin
Myosin Heavy Chains
Myotube
Research Support, Non-U.S. Gov't
Transaminases
Troponin

Anmerkungen:

Date Completed 31.08.2020

Date Revised 20.10.2023

published: Print

Citation Status MEDLINE

doi:

10.14814/phy2.14299

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM30434382X