Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization

Xitao Xie, Paul R Langlais, Xiaodong Zhang, Bradlee L. Heckmann, Alicia M. Saarinen, Lawrence J. Mandarino, Jun D Liu

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

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 β-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.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume306
Issue number12
DOIs
StatePublished - Jun 15 2014

Fingerprint

Lipase
Phosphorylation
Mutation
Adipocytes
Lipid Droplets
Lipolysis
Phosphoproteins
Viperidae
HeLa Cells
Adrenergic Agents
Proteomics
Triglycerides
Proteins
Hydrolysis
Enzymes

Keywords

  • Adipose triglyceride lipase
  • Lipid droplet
  • Lipid metabolism
  • Lipolysis
  • Phosphorylation
  • Triglyceride

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Endocrinology, Diabetes and Metabolism

Cite this

Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization. / Xie, Xitao; Langlais, Paul R; Zhang, Xiaodong; Heckmann, Bradlee L.; Saarinen, Alicia M.; Mandarino, Lawrence J.; Liu, Jun D.

In: American Journal of Physiology - Endocrinology and Metabolism, Vol. 306, No. 12, 15.06.2014.

Research output: Contribution to journalArticle

Xie, Xitao ; Langlais, Paul R ; Zhang, Xiaodong ; Heckmann, Bradlee L. ; Saarinen, Alicia M. ; Mandarino, Lawrence J. ; Liu, Jun D. / Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization. In: American Journal of Physiology - Endocrinology and Metabolism. 2014 ; Vol. 306, No. 12.
@article{4c9fd0a24a394d53bfc3db109c9ebbea,
title = "Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization",
abstract = "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 β-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.",
keywords = "Adipose triglyceride lipase, Lipid droplet, Lipid metabolism, Lipolysis, Phosphorylation, Triglyceride",
author = "Xitao Xie and Langlais, {Paul R} and Xiaodong Zhang and Heckmann, {Bradlee L.} and Saarinen, {Alicia M.} and Mandarino, {Lawrence J.} and Liu, {Jun D}",
year = "2014",
month = "6",
day = "15",
doi = "10.1152/ajpendo.00663.2013",
language = "English (US)",
volume = "306",
journal = "American Journal of Physiology - Renal Fluid and Electrolyte Physiology",
issn = "1931-857X",
publisher = "American Physiological Society",
number = "12",

}

TY - JOUR

T1 - Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization

AU - Xie, Xitao

AU - Langlais, Paul R

AU - Zhang, Xiaodong

AU - Heckmann, Bradlee L.

AU - Saarinen, Alicia M.

AU - Mandarino, Lawrence J.

AU - Liu, Jun D

PY - 2014/6/15

Y1 - 2014/6/15

N2 - 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 β-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.

AB - 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 β-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.

KW - Adipose triglyceride lipase

KW - Lipid droplet

KW - Lipid metabolism

KW - Lipolysis

KW - Phosphorylation

KW - Triglyceride

UR - http://www.scopus.com/inward/record.url?scp=84902665686&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84902665686&partnerID=8YFLogxK

U2 - 10.1152/ajpendo.00663.2013

DO - 10.1152/ajpendo.00663.2013

M3 - Article

C2 - 24801391

AN - SCOPUS:84902665686

VL - 306

JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology

JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology

SN - 1931-857X

IS - 12

ER -