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The minimal domain of adipose triglyceride lipase (ATGL) ranges until leucine 254 and can be activated and inhibited by CGI-58 and G0S2, respectively.

Cornaciu I, Boeszoermenyi A, Lindermuth H, Nagy HM, Cerk IK, Ebner C, Salzburger B, Gruber A, Schweiger M, Zechner R, Lass A, Zimmermann R, Oberer M - PLoS ONE (2011)

Bottom Line: Yet, neither an experimentally determined 3D structure nor a model of ATGL is currently available, which would help to understand how CGI-58 and G0S2 modulate ATGL's activity.Based on these data, we generated a 3D homology model for the minimal domain.Our data provide insights into the structure-function relationship of ATGL and indicate higher structural similarities in the N-terminal halves of mammalian patatin-like phospholipase domain containing proteins, (PNPLA1, -2,- 3 and -5) than originally anticipated.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Biosciences, University of Graz, Graz, Austria.

ABSTRACT
Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme of lipolysis. ATGL specifically hydrolyzes triacylglycerols (TGs), thereby generating diacylglycerols and free fatty acids. ATGL's enzymatic activity is co-activated by the protein comparative gene identification-58 (CGI-58) and inhibited by the protein G0/G1 switch gene 2 (G0S2). The enzyme is predicted to act through a catalytic dyad (Ser47, Asp166) located within the conserved patatin domain (Ile10-Leu178). Yet, neither an experimentally determined 3D structure nor a model of ATGL is currently available, which would help to understand how CGI-58 and G0S2 modulate ATGL's activity. In this study we determined the minimal active domain of ATGL. This minimal fragment of ATGL could still be activated and inhibited by CGI-58 and G0S2, respectively. Furthermore, we show that this minimal domain is sufficient for protein-protein interaction of ATGL with its regulatory proteins. Based on these data, we generated a 3D homology model for the minimal domain. It strengthens our experimental finding that amino acids between Leu178 and Leu254 are essential for the formation of a stable protein domain related to the patatin fold. Our data provide insights into the structure-function relationship of ATGL and indicate higher structural similarities in the N-terminal halves of mammalian patatin-like phospholipase domain containing proteins, (PNPLA1, -2,- 3 and -5) than originally anticipated.

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Domain organization of mouse ATGL and C-terminal truncations used in this study.Graphical representation of the predicted domain organization: in light yellow: patatin domain (residues 10–178), including the residues forming the proposed catalytic dyad (Ser47 and Asp166). Dark yellow: the 3-layer (α/β/α) sandwich (residues 10–254); Orange: the putative hydrophobic region. Red arrows indicate the 14 C-terminal deletions which were used in this study. *as shown in this work.
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pone-0026349-g001: Domain organization of mouse ATGL and C-terminal truncations used in this study.Graphical representation of the predicted domain organization: in light yellow: patatin domain (residues 10–178), including the residues forming the proposed catalytic dyad (Ser47 and Asp166). Dark yellow: the 3-layer (α/β/α) sandwich (residues 10–254); Orange: the putative hydrophobic region. Red arrows indicate the 14 C-terminal deletions which were used in this study. *as shown in this work.

Mentions: Mouse and human ATGL genes encode proteins with 486 and 504 amino acids, respectively and share 84% sequence identity. No 3D structure for ATGL is available; however sequence analysis revealed that ATGL harbors a patatin domain located between amino acids Ile10-Leu178 (Figure 1) [11]. In mammals, an entire protein family was classified as patatin-like phospholipase domain containing family (PNPLA) [12]. PNPLAs are characterized to different extents and are mostly lipid hydrolases with varying substrate specificities (e.g. TG, retinol ester, or phospholipid). Throughout all organisms, only two proteins with known 3D structures harbor the patatin domain: the name giving plant protein patatin, Pat17, and the catalytic domain of human cytosolic phospholipase A2 (cPLA2) [13], [14]. Based on similar features of ATGL with these proteins, it can be assumed that ATGL acts through a catalytic dyad similar to cPLA2 and Pat17 (Figure 1). The essential role of the putative dyad residues Ser47 and Asp166 in ATGL was experimentally confirmed by mutation studies [15], [16], [17]. In vivo, ATGL is reported to be localized in the cytoplasm, on LDs and in membranes [1], [18], [19]. LD localization is attributed to a hydrophobic stretch which is in the C-terminal half of ATGL, Val315 to Ile364 (Figure 1) [9], [20], [21]. Further indication that the catalytic activity of ATGL reside within the N-terminal portion of ATGL is based on analysis of TG hydrolase activity of C-terminally truncated proteins as found in patients with NLSDM. In living cells, these truncated ATGL variants are not capable of binding to lipid droplets and do not hydrolyze TG [15], [20], [21]. Interestingly, these truncated ATGL variants show increased TG hydrolase activity in vitro [15], [20], [21].


The minimal domain of adipose triglyceride lipase (ATGL) ranges until leucine 254 and can be activated and inhibited by CGI-58 and G0S2, respectively.

Cornaciu I, Boeszoermenyi A, Lindermuth H, Nagy HM, Cerk IK, Ebner C, Salzburger B, Gruber A, Schweiger M, Zechner R, Lass A, Zimmermann R, Oberer M - PLoS ONE (2011)

Domain organization of mouse ATGL and C-terminal truncations used in this study.Graphical representation of the predicted domain organization: in light yellow: patatin domain (residues 10–178), including the residues forming the proposed catalytic dyad (Ser47 and Asp166). Dark yellow: the 3-layer (α/β/α) sandwich (residues 10–254); Orange: the putative hydrophobic region. Red arrows indicate the 14 C-terminal deletions which were used in this study. *as shown in this work.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198459&req=5

pone-0026349-g001: Domain organization of mouse ATGL and C-terminal truncations used in this study.Graphical representation of the predicted domain organization: in light yellow: patatin domain (residues 10–178), including the residues forming the proposed catalytic dyad (Ser47 and Asp166). Dark yellow: the 3-layer (α/β/α) sandwich (residues 10–254); Orange: the putative hydrophobic region. Red arrows indicate the 14 C-terminal deletions which were used in this study. *as shown in this work.
Mentions: Mouse and human ATGL genes encode proteins with 486 and 504 amino acids, respectively and share 84% sequence identity. No 3D structure for ATGL is available; however sequence analysis revealed that ATGL harbors a patatin domain located between amino acids Ile10-Leu178 (Figure 1) [11]. In mammals, an entire protein family was classified as patatin-like phospholipase domain containing family (PNPLA) [12]. PNPLAs are characterized to different extents and are mostly lipid hydrolases with varying substrate specificities (e.g. TG, retinol ester, or phospholipid). Throughout all organisms, only two proteins with known 3D structures harbor the patatin domain: the name giving plant protein patatin, Pat17, and the catalytic domain of human cytosolic phospholipase A2 (cPLA2) [13], [14]. Based on similar features of ATGL with these proteins, it can be assumed that ATGL acts through a catalytic dyad similar to cPLA2 and Pat17 (Figure 1). The essential role of the putative dyad residues Ser47 and Asp166 in ATGL was experimentally confirmed by mutation studies [15], [16], [17]. In vivo, ATGL is reported to be localized in the cytoplasm, on LDs and in membranes [1], [18], [19]. LD localization is attributed to a hydrophobic stretch which is in the C-terminal half of ATGL, Val315 to Ile364 (Figure 1) [9], [20], [21]. Further indication that the catalytic activity of ATGL reside within the N-terminal portion of ATGL is based on analysis of TG hydrolase activity of C-terminally truncated proteins as found in patients with NLSDM. In living cells, these truncated ATGL variants are not capable of binding to lipid droplets and do not hydrolyze TG [15], [20], [21]. Interestingly, these truncated ATGL variants show increased TG hydrolase activity in vitro [15], [20], [21].

Bottom Line: Yet, neither an experimentally determined 3D structure nor a model of ATGL is currently available, which would help to understand how CGI-58 and G0S2 modulate ATGL's activity.Based on these data, we generated a 3D homology model for the minimal domain.Our data provide insights into the structure-function relationship of ATGL and indicate higher structural similarities in the N-terminal halves of mammalian patatin-like phospholipase domain containing proteins, (PNPLA1, -2,- 3 and -5) than originally anticipated.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Biosciences, University of Graz, Graz, Austria.

ABSTRACT
Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme of lipolysis. ATGL specifically hydrolyzes triacylglycerols (TGs), thereby generating diacylglycerols and free fatty acids. ATGL's enzymatic activity is co-activated by the protein comparative gene identification-58 (CGI-58) and inhibited by the protein G0/G1 switch gene 2 (G0S2). The enzyme is predicted to act through a catalytic dyad (Ser47, Asp166) located within the conserved patatin domain (Ile10-Leu178). Yet, neither an experimentally determined 3D structure nor a model of ATGL is currently available, which would help to understand how CGI-58 and G0S2 modulate ATGL's activity. In this study we determined the minimal active domain of ATGL. This minimal fragment of ATGL could still be activated and inhibited by CGI-58 and G0S2, respectively. Furthermore, we show that this minimal domain is sufficient for protein-protein interaction of ATGL with its regulatory proteins. Based on these data, we generated a 3D homology model for the minimal domain. It strengthens our experimental finding that amino acids between Leu178 and Leu254 are essential for the formation of a stable protein domain related to the patatin fold. Our data provide insights into the structure-function relationship of ATGL and indicate higher structural similarities in the N-terminal halves of mammalian patatin-like phospholipase domain containing proteins, (PNPLA1, -2,- 3 and -5) than originally anticipated.

Show MeSH
Related in: MedlinePlus