title: Phosphorylation of plastoglobular proteins in Arabidopsis thaliana.
abstract: Plastoglobules (PGs) are plastid lipid-protein particles with a small specialized proteome and metabolome. Among the 30 core PG proteins are six proteins of the ancient ABC1 atypical kinase (ABC1K) family and their locations in an Arabidopsis mRNA-based co-expression network suggested central regulatory roles. To identify candidate ABC1K targets and a possible ABC1K hierarchical phosphorylation network within the chloroplast PG proteome, we searched Arabidopsis phosphoproteomics data from publicly available sources. Evaluation of underlying spectra and/or associated information was challenging for a variety of reasons, but supported pSer sites and a few pThr sites in nine PG proteins, including five FIBRILLINS. PG phosphorylation motifs are discussed in the context of possible responsible kinases. The challenges of collection and evaluation of published Arabidopsis phosphorylation data are discussed, illustrating the importance of deposition of all mass spectrometry data in well-organized repositories such as PRIDE and ProteomeXchange. This study provides a starting point for experimental testing of phosho-sites in PG proteins and also suggests that phosphoproteomics studies specifically designed toward the PG proteome and its ABC1K are needed to understand phosphorylation networks in these specialized particles.
authors.affiliation: Section of Plant Biology, School of Integrated Plant Science (SIPS), Cornell University, Ithaca, NY 14853, USA.
authors.forename: Jens N
authors.initials: JN
authors.lastname: Lohscheider
authors.affiliation: Section of Plant Biology, School of Integrated Plant Science (SIPS), Cornell University, Ithaca, NY 14853, USA.
authors.forename: Giulia
authors.initials: G
authors.lastname: Friso
authors.affiliation: Section of Plant Biology, School of Integrated Plant Science (SIPS), Cornell University, Ithaca, NY 14853, USA kv35@cornell.edu.
authors.forename: Klaas J
authors.identifier: 0000-0001-9536-0487
authors.initials: KJ
authors.lastname: van Wijk
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D020543:Proteome
chemical_list: D029681:Arabidopsis Proteins; D020543:Proteome; D011494:Protein Kinases
keywords: ABC1 kinase; FIBRILLIN; chloroplast; meta-analysis; phosphorylation; plastoglobule; proteome.