Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization.
Am J Physiol Endocrinol Metab
; 306(12): E1449-59, 2014 Jun 15.
Article
em En
| MEDLINE
| ID: mdl-24801391
Adipose triglyceride lipase (ATGL), the rate-limiting enzyme for triacylglycerol (TG) hydrolysis, has long been known to be a phosphoprotein. However, the potential phosphorylation events that are involved in the regulation of ATGL function remain incompletely defined. Here, using a combinatorial proteomics approach, we obtained evidence that at least eight different sites of ATGL can be phosphorylated in adipocytes. Among them, Thr³7² resides within the hydrophobic region known to mediate lipid droplet (LD) targeting. Although it had no impact on the TG hydrolase activity, substitution of phosphorylation-mimic Asp for Thr³7² eliminated LD localization and LD-degrading capacity of ATGL expressed in HeLa cells. In contrast, mutation of Thr³7² to Ala gave a protein that bound LDs and functioned the same as the wild-type protein. In nonstimulated adipocytes, the Asp mutation led to decreased LD association and basal lipolytic activity of ATGL, whereas the Ala mutation produced opposite effects. Moreover, the LD translocation of ATGL upon ß-adrenergic stimulation was also compromised by the Asp mutation. In accord with these findings, the Ala mutation promoted and the Asp mutation attenuated the capacity of ATGL to mediate lipolysis in adipocytes under both basal and stimulated conditions. Collectively, these studies identified Thr³7² as a novel phosphorylation site that may play a critical role in determining subcellular distribution as well as lipolytic action of ATGL.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Treonina
/
Triglicerídeos
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Processamento de Proteína Pós-Traducional
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Grânulos Citoplasmáticos
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Adipócitos Brancos
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Lipase
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Lipólise
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Animals
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Humans
Idioma:
En
Revista:
Am J Physiol Endocrinol Metab
Assunto da revista:
ENDOCRINOLOGIA
/
FISIOLOGIA
/
METABOLISMO
Ano de publicação:
2014
Tipo de documento:
Article