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The Role of RaxST, a Prokaryotic Sulfotransferase, and RaxABC, a Putative Type I Secretion System, in Activation of the Rice XA21-Mediated Immune Response.

Ronald PC - Scientifica (Cairo) (2014)

Bottom Line: Tyrosine sulfation is an important posttranslational modification that determines the outcome of serious diseases in plants and animals.We have recently demonstrated that the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) carries a functional sulfotransferase (RaxST). raxST is required for activation of rice Xa21-mediated immunity indicating the critical, but unknown, function of raxST in mediating the Xoo/rice interaction.The raxST gene resides in the same operon (raxSTAB) as components of a predicted type I secretion and processing system (RaxA and RaxB).

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, USA.

ABSTRACT
Tyrosine sulfation is an important posttranslational modification that determines the outcome of serious diseases in plants and animals. We have recently demonstrated that the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) carries a functional sulfotransferase (RaxST). raxST is required for activation of rice Xa21-mediated immunity indicating the critical, but unknown, function of raxST in mediating the Xoo/rice interaction. The raxST gene resides in the same operon (raxSTAB) as components of a predicted type I secretion and processing system (RaxA and RaxB). These observations suggest a model where RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS.

No MeSH data available.


Related in: MedlinePlus

Working model for the synthesis and secretion of proteins required for activation of XA21-mediated immunity (encoded by rax genes). In this model, the adenosine-5′-triphosphate (ATP) sulfurylase RaxP and the adenosine-5′-phosphosulfate (APS) kinase RaxQ catalyze the production of the universal sulfuryl group donor 3′-phosphoadenosine 5′-phosphosulfate (PAPS). The RaxST sulfotransferase utilizes PAPS as a substrate. We hypothesize that RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS.
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fig1: Working model for the synthesis and secretion of proteins required for activation of XA21-mediated immunity (encoded by rax genes). In this model, the adenosine-5′-triphosphate (ATP) sulfurylase RaxP and the adenosine-5′-phosphosulfate (APS) kinase RaxQ catalyze the production of the universal sulfuryl group donor 3′-phosphoadenosine 5′-phosphosulfate (PAPS). The RaxST sulfotransferase utilizes PAPS as a substrate. We hypothesize that RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS.

Mentions: The second class of rax genes is involved in sulfation. raxP and raxQ, identified through a forward genetics screen [19], encode an ATP sulfurylase and an adenosine-5′-phosphosulfate (APS) kinase. These proteins function in concert to produce 3′-phosphoadenosine 5′-phosphosulfate (PAPS), the universal sulfuryl group donor [19]. This class also includes the raxST-encoded sulfotransferase. raxST resides in the same operon with raxA and raxB (raxSTAB), suggesting that this group of proteins may target similar substrates and/or control a similar biological process [15]. Strains carrying mutations in these rax genes compromise the ability of Xoo to activate XA21-mediated immunity. In support of a role for these genes in a shared biological process, we and others have demonstrated that raxST and other rax genes are transcriptionally regulated by cell density, where high cell density induces and low cell density represses gene expression [20]. A model for rax gene function is shown in Figure 1.


The Role of RaxST, a Prokaryotic Sulfotransferase, and RaxABC, a Putative Type I Secretion System, in Activation of the Rice XA21-Mediated Immune Response.

Ronald PC - Scientifica (Cairo) (2014)

Working model for the synthesis and secretion of proteins required for activation of XA21-mediated immunity (encoded by rax genes). In this model, the adenosine-5′-triphosphate (ATP) sulfurylase RaxP and the adenosine-5′-phosphosulfate (APS) kinase RaxQ catalyze the production of the universal sulfuryl group donor 3′-phosphoadenosine 5′-phosphosulfate (PAPS). The RaxST sulfotransferase utilizes PAPS as a substrate. We hypothesize that RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4216712&req=5

fig1: Working model for the synthesis and secretion of proteins required for activation of XA21-mediated immunity (encoded by rax genes). In this model, the adenosine-5′-triphosphate (ATP) sulfurylase RaxP and the adenosine-5′-phosphosulfate (APS) kinase RaxQ catalyze the production of the universal sulfuryl group donor 3′-phosphoadenosine 5′-phosphosulfate (PAPS). The RaxST sulfotransferase utilizes PAPS as a substrate. We hypothesize that RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS.
Mentions: The second class of rax genes is involved in sulfation. raxP and raxQ, identified through a forward genetics screen [19], encode an ATP sulfurylase and an adenosine-5′-phosphosulfate (APS) kinase. These proteins function in concert to produce 3′-phosphoadenosine 5′-phosphosulfate (PAPS), the universal sulfuryl group donor [19]. This class also includes the raxST-encoded sulfotransferase. raxST resides in the same operon with raxA and raxB (raxSTAB), suggesting that this group of proteins may target similar substrates and/or control a similar biological process [15]. Strains carrying mutations in these rax genes compromise the ability of Xoo to activate XA21-mediated immunity. In support of a role for these genes in a shared biological process, we and others have demonstrated that raxST and other rax genes are transcriptionally regulated by cell density, where high cell density induces and low cell density represses gene expression [20]. A model for rax gene function is shown in Figure 1.

Bottom Line: Tyrosine sulfation is an important posttranslational modification that determines the outcome of serious diseases in plants and animals.We have recently demonstrated that the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) carries a functional sulfotransferase (RaxST). raxST is required for activation of rice Xa21-mediated immunity indicating the critical, but unknown, function of raxST in mediating the Xoo/rice interaction.The raxST gene resides in the same operon (raxSTAB) as components of a predicted type I secretion and processing system (RaxA and RaxB).

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, USA.

ABSTRACT
Tyrosine sulfation is an important posttranslational modification that determines the outcome of serious diseases in plants and animals. We have recently demonstrated that the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) carries a functional sulfotransferase (RaxST). raxST is required for activation of rice Xa21-mediated immunity indicating the critical, but unknown, function of raxST in mediating the Xoo/rice interaction. The raxST gene resides in the same operon (raxSTAB) as components of a predicted type I secretion and processing system (RaxA and RaxB). These observations suggest a model where RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS.

No MeSH data available.


Related in: MedlinePlus