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Identification of Giardia lamblia DHHC proteins and the role of protein S-palmitoylation in the encystation process.

Merino MC, Zamponi N, Vranych CV, Touz MC, Rópolo AS - PLoS Negl Trop Dis (2014)

Bottom Line: With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome.These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades.Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina.

ABSTRACT
Protein S-palmitoylation, a hydrophobic post-translational modification, is performed by protein acyltransferases that have a common DHHC Cys-rich domain (DHHC proteins), and provides a regulatory switch for protein membrane association. In this work, we analyzed the presence of DHHC proteins in the protozoa parasite Giardia lamblia and the function of the reversible S-palmitoylation of proteins during parasite differentiation into cyst. Two specific events were observed: encysting cells displayed a larger amount of palmitoylated proteins, and parasites treated with palmitoylation inhibitors produced a reduced number of mature cysts. With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome. These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades. Although all Giardia DHHC proteins were found to be present in trophozoites and encysting cells, these proteins showed a different intracellular localization in trophozoites and seemed to be differently involved in the encystation process when they were overexpressed. dhhc transgenic parasites showed a different pattern of cyst wall protein expression and yielded different amounts of mature cysts when they were induced to encyst. Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation.

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Sequence alignment and schematic drawing of Giardia DHHC proteins.(A) Multiple Sequence alignment of DHHC proteins shows conserved regions. The amino acid sequences of the total set of Giardia DHHC proteins, Erf2 (Yeast), ZDHHC4 (Human), and PF11_0167 (Plasmodium falciparum) were aligned using T-Coffee software [104]. The conserved DHHC-CRD domain and the DPG and TTxE motifs are indicated in bold. Positions exhibiting absolute identity are shown in pink, and high and lower amino acid similarities in green and yellow, respectively. (B) Schematic representation of the primary structure of Giardia DHHC proteins. The domains were searched using SMART (http://smart.embl-heidelberg.de) [105], [106]. Transmembrane domains were predicted using TMHMM (http://www.cbs.dtu.dk/services/TMHMM) [107] and TMPred (http://www.ch.embnet.org/software/TMPRED_form.html) with default settings. Signal peptides were predicted with signalP (http://www.cbs.dtu.dk/services/SignalP) [108].
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pntd-0002997-g003: Sequence alignment and schematic drawing of Giardia DHHC proteins.(A) Multiple Sequence alignment of DHHC proteins shows conserved regions. The amino acid sequences of the total set of Giardia DHHC proteins, Erf2 (Yeast), ZDHHC4 (Human), and PF11_0167 (Plasmodium falciparum) were aligned using T-Coffee software [104]. The conserved DHHC-CRD domain and the DPG and TTxE motifs are indicated in bold. Positions exhibiting absolute identity are shown in pink, and high and lower amino acid similarities in green and yellow, respectively. (B) Schematic representation of the primary structure of Giardia DHHC proteins. The domains were searched using SMART (http://smart.embl-heidelberg.de) [105], [106]. Transmembrane domains were predicted using TMHMM (http://www.cbs.dtu.dk/services/TMHMM) [107] and TMPred (http://www.ch.embnet.org/software/TMPRED_form.html) with default settings. Signal peptides were predicted with signalP (http://www.cbs.dtu.dk/services/SignalP) [108].

Mentions: PATs, the discovery of which has been crucial for the enzymology of palmitoylation, are a widespread evolutionary family of proteins [16], [82] ranging from eight in Saccharomyces cerevisiae[82], twelve in Trypanosoma brucei[27], eighteen in Toxoplasma gondii[25], twelve in Plasmodium[26], [25] to twenty-three members in humans [82]. To identify the complete set of Giardia putative PATs, we performed a HMMER search against the Giardia complete proteome using a DHHC PAT HMMer profile from Pfam (zf-DHHC). As shown in figure 3A, we found nine DHHC proteins in the Giardia proteome that displayed conserved sequences when compared to other organisms: i) the DHHC-CRD domain, ii) the two short motifs DPG (aspartate-proline-glycine) and iii) TTxE (threonine-threonine-any-glutamate) motif [20], [82]. One protein (gla_8711) contained a DHYC amino acid motif, instead of the canonical DHHC motif. However, this DHYC motif has been reported to be functional in the yeast PAT Akr1 [16].


Identification of Giardia lamblia DHHC proteins and the role of protein S-palmitoylation in the encystation process.

Merino MC, Zamponi N, Vranych CV, Touz MC, Rópolo AS - PLoS Negl Trop Dis (2014)

Sequence alignment and schematic drawing of Giardia DHHC proteins.(A) Multiple Sequence alignment of DHHC proteins shows conserved regions. The amino acid sequences of the total set of Giardia DHHC proteins, Erf2 (Yeast), ZDHHC4 (Human), and PF11_0167 (Plasmodium falciparum) were aligned using T-Coffee software [104]. The conserved DHHC-CRD domain and the DPG and TTxE motifs are indicated in bold. Positions exhibiting absolute identity are shown in pink, and high and lower amino acid similarities in green and yellow, respectively. (B) Schematic representation of the primary structure of Giardia DHHC proteins. The domains were searched using SMART (http://smart.embl-heidelberg.de) [105], [106]. Transmembrane domains were predicted using TMHMM (http://www.cbs.dtu.dk/services/TMHMM) [107] and TMPred (http://www.ch.embnet.org/software/TMPRED_form.html) with default settings. Signal peptides were predicted with signalP (http://www.cbs.dtu.dk/services/SignalP) [108].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109852&req=5

pntd-0002997-g003: Sequence alignment and schematic drawing of Giardia DHHC proteins.(A) Multiple Sequence alignment of DHHC proteins shows conserved regions. The amino acid sequences of the total set of Giardia DHHC proteins, Erf2 (Yeast), ZDHHC4 (Human), and PF11_0167 (Plasmodium falciparum) were aligned using T-Coffee software [104]. The conserved DHHC-CRD domain and the DPG and TTxE motifs are indicated in bold. Positions exhibiting absolute identity are shown in pink, and high and lower amino acid similarities in green and yellow, respectively. (B) Schematic representation of the primary structure of Giardia DHHC proteins. The domains were searched using SMART (http://smart.embl-heidelberg.de) [105], [106]. Transmembrane domains were predicted using TMHMM (http://www.cbs.dtu.dk/services/TMHMM) [107] and TMPred (http://www.ch.embnet.org/software/TMPRED_form.html) with default settings. Signal peptides were predicted with signalP (http://www.cbs.dtu.dk/services/SignalP) [108].
Mentions: PATs, the discovery of which has been crucial for the enzymology of palmitoylation, are a widespread evolutionary family of proteins [16], [82] ranging from eight in Saccharomyces cerevisiae[82], twelve in Trypanosoma brucei[27], eighteen in Toxoplasma gondii[25], twelve in Plasmodium[26], [25] to twenty-three members in humans [82]. To identify the complete set of Giardia putative PATs, we performed a HMMER search against the Giardia complete proteome using a DHHC PAT HMMer profile from Pfam (zf-DHHC). As shown in figure 3A, we found nine DHHC proteins in the Giardia proteome that displayed conserved sequences when compared to other organisms: i) the DHHC-CRD domain, ii) the two short motifs DPG (aspartate-proline-glycine) and iii) TTxE (threonine-threonine-any-glutamate) motif [20], [82]. One protein (gla_8711) contained a DHYC amino acid motif, instead of the canonical DHHC motif. However, this DHYC motif has been reported to be functional in the yeast PAT Akr1 [16].

Bottom Line: With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome.These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades.Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina.

ABSTRACT
Protein S-palmitoylation, a hydrophobic post-translational modification, is performed by protein acyltransferases that have a common DHHC Cys-rich domain (DHHC proteins), and provides a regulatory switch for protein membrane association. In this work, we analyzed the presence of DHHC proteins in the protozoa parasite Giardia lamblia and the function of the reversible S-palmitoylation of proteins during parasite differentiation into cyst. Two specific events were observed: encysting cells displayed a larger amount of palmitoylated proteins, and parasites treated with palmitoylation inhibitors produced a reduced number of mature cysts. With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome. These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades. Although all Giardia DHHC proteins were found to be present in trophozoites and encysting cells, these proteins showed a different intracellular localization in trophozoites and seemed to be differently involved in the encystation process when they were overexpressed. dhhc transgenic parasites showed a different pattern of cyst wall protein expression and yielded different amounts of mature cysts when they were induced to encyst. Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation.

Show MeSH
Related in: MedlinePlus