Post-translational modification of barley 14-3-3A is isoform-specific and involves removal of the hypervariable C-terminus.
The 14-3-3 protein family is a family of regulatory proteins involved in diverse cellular processes. In a previous study of regulation of individual 14-3-3 isoforms in the germinating barley embryo, we found that a post-translationally modified, 28 kDa form of 14-3-3A was present in specific cell fractions of the germinated embryo. In the present study, we identify the nature of the modification of 14-3-3A, and show that the 28 kDa doublet is the result of cleavage of the C-terminus. The 28 kDa forms of 14-3-3A lack ten or twelve amino acid residues at the non-conserved C-terminus of the protein, respectively. Barley 14-3-3B and 14-3-3C are not modified in a similar way. Like the 30 kDa form, in vitro produced 28 kDa 14-3-3A is still capable of binding AHA2 H+-ATPase in an overlay assay. Our results show a novel isoform-specific post-translational modification of 14-3-3 proteins that is regulated in a tissue-specific and developmental way.
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D018525:Germination; D001467:Hordeum / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D006180:Proton-Translocating ATPases / Q000378:metabolism; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism*
D048948:14-3-3 Proteins; D029681:Arabidopsis Proteins; D020033:Protein Isoforms; D014446:Tyrosine 3-Monooxygenase; D006180:Proton-Translocating ATPases