Limits...
Site-Specific Ser/Thr/Tyr Phosphoproteome of Sinorhizobium meliloti at Stationary Phase.

Liu T, Tian CF, Chen WX - PLoS ONE (2015)

Bottom Line: Phosphoproteins identified in S. meliloti showed a wide distribution pattern regarding to functional categories, such as replication, transcription, translation, posttranslational modification, transport and metabolism of amino acids, carbohydrate, inorganic ion, succinoglycan etc.Moreover, phosphorylation in proteins involved in processes related to rhizobial adaptation was also discussed, such as those identified in SMa0114 and PhaP2 (polyhydroxybutyrate synthesis), ActR (pH stress and microaerobic adaption), SupA (potassium stress), chaperonin GroEL2 (viability and potentially symbiosis), and ExoP (succinoglycan synthesis and secretion).These Ser/Thr/Tyr phosphosites identified herein would be helpful for our further investigation and understanding of the role of phosphorylation in rhizobial physiology.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Agrobiotechnology, and College of Biological Sciences, China Agricultural University, Beijing, China; Key Laboratory of Soil Microbiology, Ministry of Agriculture, China Agricultural University, Beijing, China; Rhizobium Research Center, China Agricultural University, Beijing, China.

ABSTRACT
Sinorhizobium meliloti, a facultative microsymbiont of alfalfa, should fine-tune its cellular processes to live saprophytically in soils characterized with limited nutrients and diverse stresses. In this study, TiO2 enrichment and LC-MS/MS were used to uncover the site-specific Ser/Thr/Tyr phosphoproteome of S. meliloti in minimum medium at stationary phase. There are a total of 96 unique phosphorylated sites, with a Ser/Thr/Tyr distribution of 63:28:5, in 77 proteins. Phosphoproteins identified in S. meliloti showed a wide distribution pattern regarding to functional categories, such as replication, transcription, translation, posttranslational modification, transport and metabolism of amino acids, carbohydrate, inorganic ion, succinoglycan etc. Ser/Thr/Tyr phosphosites identified within the conserved motif in proteins of key cellular function indicate a crucial role of phosphorylation in modulating cellular physiology. Moreover, phosphorylation in proteins involved in processes related to rhizobial adaptation was also discussed, such as those identified in SMa0114 and PhaP2 (polyhydroxybutyrate synthesis), ActR (pH stress and microaerobic adaption), SupA (potassium stress), chaperonin GroEL2 (viability and potentially symbiosis), and ExoP (succinoglycan synthesis and secretion). These Ser/Thr/Tyr phosphosites identified herein would be helpful for our further investigation and understanding of the role of phosphorylation in rhizobial physiology.

No MeSH data available.


Phosphoproteins identified in carbohydrate metabolism.Gray box indicates phosphoproteins. PEP, phosphoenolpyruvate.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4581636&req=5

pone.0139143.g004: Phosphoproteins identified in carbohydrate metabolism.Gray box indicates phosphoproteins. PEP, phosphoenolpyruvate.

Mentions: As shown in Fig 4, Pgm (phosphoglucomutase, EC:5.4.2.2, pS112) catalyzes the reaction from alpha-D-glucose-1-phosphate to D-glucose-6-phosphate, which could be further converted to fructose-6-P by Pgi (glucose-6-phosphate isomerase) in the glycolysis pathway. Another phosphorylated glycolytic protein is Gap (glyceraldehyde-3-phosphate dehydrogenase, EC:1.2.1.12, pT210, pS211), which dehydrogenates glyceraldehyde-3-phosphate and adds an inorganic phosphate forming 1,3-bisphosphoglycerate. Moreover, Pgl (6-phosphogluconolactoase, EC:3.1.1.31, pT45 and pT136) and RpiB (ribose 5-phosphate isomerase B, EC:5.3.1.6, pS95) in pentose phosphate pathway, GlmM (phosphoglucosamine mutase, EC:5.4.2.10, pS102) in amino sugar metabolism, ManB (phosphomannomutase, EC:5.4.2.8, pS99) in mannose metabolism, and SMc02846 (D-fructokinase, EC:2.7.1.4, pS198) in fructose metabolism were also phosphorylated at Ser and/or Thr. Certain phosphosites in these proteins with key cellular function were also reported in other bacteria [23, 24, 27]. For example, AAALSMIPT(pS)TGAAK in S. meliloti Gap is similar to those of L. lactis and L. monocytogenes [27]. GlmM is phosphorylated at S102 (ADIGVMISA(pS)HNAFR) in S. meliloti, and E. coli GlmM with the same conserved pS102 is essential in cell wall peptidoglycan and lipopolysaccharide biosynthesis [64, 65]. Notably, two phosphorylated periplasmic proteins were also identified herein, a putative dicarboxylate transporter (SMb21438, pS9) and a putative sugar transporter SupA (SMb20484, pT27). The expression of SupA could be induced by potassium and is essential for the adaptation of S. meliloti to the high level of potassium [66]. PHB granules assist bacterial survival under nutrient-fluctuating conditions. PhaP2, one of the two major phasins (PHB granule-associated proteins) involved in regulating PHB synthesis and granule formation in S. meliloti [67], was found to be phosphorylated at Ser40 and Ser43.


Site-Specific Ser/Thr/Tyr Phosphoproteome of Sinorhizobium meliloti at Stationary Phase.

Liu T, Tian CF, Chen WX - PLoS ONE (2015)

Phosphoproteins identified in carbohydrate metabolism.Gray box indicates phosphoproteins. PEP, phosphoenolpyruvate.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581636&req=5

pone.0139143.g004: Phosphoproteins identified in carbohydrate metabolism.Gray box indicates phosphoproteins. PEP, phosphoenolpyruvate.
Mentions: As shown in Fig 4, Pgm (phosphoglucomutase, EC:5.4.2.2, pS112) catalyzes the reaction from alpha-D-glucose-1-phosphate to D-glucose-6-phosphate, which could be further converted to fructose-6-P by Pgi (glucose-6-phosphate isomerase) in the glycolysis pathway. Another phosphorylated glycolytic protein is Gap (glyceraldehyde-3-phosphate dehydrogenase, EC:1.2.1.12, pT210, pS211), which dehydrogenates glyceraldehyde-3-phosphate and adds an inorganic phosphate forming 1,3-bisphosphoglycerate. Moreover, Pgl (6-phosphogluconolactoase, EC:3.1.1.31, pT45 and pT136) and RpiB (ribose 5-phosphate isomerase B, EC:5.3.1.6, pS95) in pentose phosphate pathway, GlmM (phosphoglucosamine mutase, EC:5.4.2.10, pS102) in amino sugar metabolism, ManB (phosphomannomutase, EC:5.4.2.8, pS99) in mannose metabolism, and SMc02846 (D-fructokinase, EC:2.7.1.4, pS198) in fructose metabolism were also phosphorylated at Ser and/or Thr. Certain phosphosites in these proteins with key cellular function were also reported in other bacteria [23, 24, 27]. For example, AAALSMIPT(pS)TGAAK in S. meliloti Gap is similar to those of L. lactis and L. monocytogenes [27]. GlmM is phosphorylated at S102 (ADIGVMISA(pS)HNAFR) in S. meliloti, and E. coli GlmM with the same conserved pS102 is essential in cell wall peptidoglycan and lipopolysaccharide biosynthesis [64, 65]. Notably, two phosphorylated periplasmic proteins were also identified herein, a putative dicarboxylate transporter (SMb21438, pS9) and a putative sugar transporter SupA (SMb20484, pT27). The expression of SupA could be induced by potassium and is essential for the adaptation of S. meliloti to the high level of potassium [66]. PHB granules assist bacterial survival under nutrient-fluctuating conditions. PhaP2, one of the two major phasins (PHB granule-associated proteins) involved in regulating PHB synthesis and granule formation in S. meliloti [67], was found to be phosphorylated at Ser40 and Ser43.

Bottom Line: Phosphoproteins identified in S. meliloti showed a wide distribution pattern regarding to functional categories, such as replication, transcription, translation, posttranslational modification, transport and metabolism of amino acids, carbohydrate, inorganic ion, succinoglycan etc.Moreover, phosphorylation in proteins involved in processes related to rhizobial adaptation was also discussed, such as those identified in SMa0114 and PhaP2 (polyhydroxybutyrate synthesis), ActR (pH stress and microaerobic adaption), SupA (potassium stress), chaperonin GroEL2 (viability and potentially symbiosis), and ExoP (succinoglycan synthesis and secretion).These Ser/Thr/Tyr phosphosites identified herein would be helpful for our further investigation and understanding of the role of phosphorylation in rhizobial physiology.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Agrobiotechnology, and College of Biological Sciences, China Agricultural University, Beijing, China; Key Laboratory of Soil Microbiology, Ministry of Agriculture, China Agricultural University, Beijing, China; Rhizobium Research Center, China Agricultural University, Beijing, China.

ABSTRACT
Sinorhizobium meliloti, a facultative microsymbiont of alfalfa, should fine-tune its cellular processes to live saprophytically in soils characterized with limited nutrients and diverse stresses. In this study, TiO2 enrichment and LC-MS/MS were used to uncover the site-specific Ser/Thr/Tyr phosphoproteome of S. meliloti in minimum medium at stationary phase. There are a total of 96 unique phosphorylated sites, with a Ser/Thr/Tyr distribution of 63:28:5, in 77 proteins. Phosphoproteins identified in S. meliloti showed a wide distribution pattern regarding to functional categories, such as replication, transcription, translation, posttranslational modification, transport and metabolism of amino acids, carbohydrate, inorganic ion, succinoglycan etc. Ser/Thr/Tyr phosphosites identified within the conserved motif in proteins of key cellular function indicate a crucial role of phosphorylation in modulating cellular physiology. Moreover, phosphorylation in proteins involved in processes related to rhizobial adaptation was also discussed, such as those identified in SMa0114 and PhaP2 (polyhydroxybutyrate synthesis), ActR (pH stress and microaerobic adaption), SupA (potassium stress), chaperonin GroEL2 (viability and potentially symbiosis), and ExoP (succinoglycan synthesis and secretion). These Ser/Thr/Tyr phosphosites identified herein would be helpful for our further investigation and understanding of the role of phosphorylation in rhizobial physiology.

No MeSH data available.