scholarly journals Regulatory Phosphorylation of Bacterial-Type PEP Carboxylase by the Ca2+-Dependent Protein Kinase RcCDPK1 in Developing Castor Oil Seeds

2017 ◽  
Vol 174 (2) ◽  
pp. 1012-1027 ◽  
Author(s):  
Sheng Ying ◽  
Allyson T. Hill ◽  
Michal Pyc ◽  
Erin M. Anderson ◽  
Wayne A. Snedden ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Castor Oil ◽  
Dependent Protein Kinase ◽  
Pep Carboxylase ◽  
Oil Seeds ◽  
Regulatory Phosphorylation ◽  
Dependent Protein ◽  
Bacterial Type

Phosphorylation of bacterial-type phosphoenolpyruvate carboxylase by a Ca2+-dependent protein kinase suggests a link between Ca2+ signalling and anaplerotic pathway control in developing castor oil seeds

2014 ◽  
Vol 458 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Allyson T. Hill ◽  
Sheng Ying ◽  
William C. Plaxton
Keyword(s):  
Protein Kinase ◽  
Phosphoenolpyruvate Carboxylase ◽  
Castor Oil ◽  
Dependent Protein Kinase ◽  
Oil Seeds ◽  
Dependent Protein ◽  
Bacterial Type ◽  
Anaplerotic Pathway

Inhibitory Ser451 phosphorylation of bacterial-type phosphoenolpyruvate carboxylase subunits of the Class-2 PEPC hetero-octameric complex of developing castor beans is catalysed by a Ca2+-dependent protein kinase. This suggests a relationship between Ca2+ signalling and the control of anaplerosis in developing oil seeds.

The calcium-dependent protein kinase RcCDPK2 phosphorylates sucrose synthase at Ser11 in developing castor oil seeds

2016 ◽  
Vol 473 (20) ◽  
pp. 3667-3682 ◽  
Author(s):  
Eric T. Fedosejevs ◽  
Suzanne A. Gerdis ◽  
Sheng Ying ◽  
Michal Pyc ◽  
Erin M. Anderson ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Sucrose Synthase ◽  
Castor Oil ◽  
Initial Reaction ◽  
Suspension Cells ◽  
Dependent Protein Kinase ◽  
Oil Seeds ◽  
Tobacco Suspension Cells ◽  
Dependent Protein ◽  
K Activity

Imported sucrose is cleaved by sucrose synthase (SUS) as a critical initial reaction in the biosynthesis of storage end-products by developing seeds. Although SUS is phosphorylated at a conserved seryl residue by an apparent CDPK (Ca2+-dependent protein kinase) in diverse plant tissues, the functions and mechanistic details of this process remain obscure. Thus, the native CDPK that phosphorylates RcSUS1 (Ricinus communis SUS1) at Ser11 in developing COS (castor oil seeds) was highly purified and identified as RcCDPK2 by MS/MS. Purified RcSUS1-K (-kinase) and heterologously expressed RcCDPK2 catalyzed Ca2+-dependent Ser11 phosphorylation of RcSUS1 and its corresponding dephosphopeptide, while exhibiting a high affinity for free Ca2+ ions [K0.5(Ca2+) < 0.4 µM]. RcSUS1-K activity, RcCDPK2 expression, and RcSUS1 Ser11 phosphorylation peaked during early COS development and then declined in parallel. The elimination of sucrose import via fruit excision triggered RcSUS1 dephosphorylation but did not alter RcSUS1-K activity, suggesting a link between sucrose signaling and posttranslational RcCDPK2 control. Both RcCDPK2-mCherry and RcSUS1-EYFP co-localized throughout the cytosol when transiently co-expressed in tobacco suspension cells, although RcCDPK2-mCherry was also partially localized to the nucleus. Subcellular fractionation revealed that ∼20% of RcSUS1-K activity associates with microsomal membranes in developing COS, as does RcSUS1. In contrast with RcCDPK1, which catalyzes inhibitory phosphorylation of COS bacterial-type phosphoenolpyruvate carboxylase at Ser451, RcCDPK2 exhibited broad substrate specificity, a wide pH–activity profile centered at pH 8.5, and insensitivity to metabolite effectors or thiol redox status. Our combined results indicate a possible link between cytosolic Ca2+-signaling and the control of photosynthate partitioning during COS development.

The bacterial-type phosphoenolpyruvate carboxylase isozyme from developing castor oil seeds is subject to in vivo regulatory phosphorylation at serine-451

FEBS Letters ◽  
2012 ◽  
Vol 586 (7) ◽  
pp. 1049-1054 ◽  
Author(s):  
Katie J. Dalziel ◽  
Brendan O'Leary ◽  
Carolyne Brikis ◽  
Srinath K. Rao ◽  
Yi-Min She ◽  
...  
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Castor Oil ◽  
Oil Seeds ◽  
Regulatory Phosphorylation ◽  
Bacterial Type
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