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Abstract

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.

The Giardia duodenalis 14-3-3 Protein Is Post-translationally Modified by Phosphorylation and Polyglycylation of the C-terminal Tail

“…The affinity of both the high and low glycylated g14-3-3 for the GST-difopein is comparable, since the relative amount of the two forms was constant before and after the affinity purification. This result is also in agreement with the observation that the binding affinity of human 14-3-3 C-terminal-tagged with green fluorescent protein is not altered (41), although a quantitative assay that includes a non-polyglycylated g14-3-3 would be necessary to fully support our result.…”

“…The truncation does not seem to alter the binding property, yet it excludes the protein from the nucleus (41).…”

Genome-Wide Identification and Expression Analysis of the 14-3-3 (TFT) Gene Family in Tomato, and the Role of SlTFT4 in Salt Stress

“…They have different structural features of exons and introns, and the intron phase in the ε group is diverse and relatively less conserved than that in the non-ε group, but both contain only the same protein structural domain, suggesting that their main functions may be consistent. However, although the central region of each SlTFT subgroup member is highly conserved, there are variations in the motifs within the N-terminal (affecting the binding to different membranes) and the C-terminal (directly involved in interactions with target proteins) and the structural domains, which may generate functional specificity while forming many heterodimers due to their being the core structures of the 14-3-3 proteins as they perform their different functions [61,62]. Our predicted subcellular localization results indicate that SlTFTs are mainly located in the cytoplasm, with individual distribution in the nucleus, while our transmembrane helix prediction results indicate that the majority of SlTFTs have no transmembrane helix and are probably membrane proteins.…”