Protein phosphorylation plays an essential role in nearly all aspects of life cycle. Ethylene linear signal pathway has been established through molecular genetic studies on Arabidopsis. Because protein phosphorylation plays a key role in ethylene signaling, the functional phosphoproteomics is adopted to study the possible existence of multiple ethylene signal pathways.

Previously, our laboratory has discovered 5 ethylene regulated consensus protein phosphorylation motifs, including PRVD/GS̲x. 20 proteins sharing PRVD/GS̲x were randomly selected, in which ERF110 is included.

My research focused on the in vitro validation of all 20 peptides, and ERF110’s in vivo validation and biological function.

Results of in vitro validation showed that 6 out of the 20 synthesized peptides could be...[ Read more ]

Protein phosphorylation plays an essential role in nearly all aspects of life cycle. Ethylene linear signal pathway has been established through molecular genetic studies on Arabidopsis. Because protein phosphorylation plays a key role in ethylene signaling, the functional phosphoproteomics is adopted to study the possible existence of multiple ethylene signal pathways.

Previously, our laboratory has discovered 5 ethylene regulated consensus protein phosphorylation motifs, including PRVD/GS̲x. 20 proteins sharing PRVD/GS̲x were randomly selected, in which ERF110 is included.

My research focused on the in vitro validation of all 20 peptides, and ERF110’s in vivo validation and biological function.

Results of in vitro validation showed that 6 out of the 20 synthesized peptides could be phosphorylated, including ERF110. Then, ERF110 was overexpressed in Arabidopsis. Results showed that ERF110 was indeed phosphorylated in vivo at the predicted phosphorylation site Ser₅₃.

Over-expression of ERF110 results in a bushy phenotype in wild type and ein2-5, but not in etr1-3, suggesting the presence of a distinct ethylene signal pathway independent to EIN2 that regulates the bolting. However, over-expression ERF110 in etr1-3 rescues the deficient triple response of this mutant, suggesting that ERF110 is necessary but not sufficient for triple response. Conversion of the Ser₅₃ to Ala₅₃ reduces the bushy phenotype significantly, and could not rescue the triple response phenotype. But conversion of the Ser₅₃ to Asp₅₃ still keeps the bushy phenotype. All these data suggested the importance of the phosphorylation site Ser₅₃.

ERF110 is constitutively expressed in the wild type, ein2-5 and etr1-3 with or without ethylene treatment, demonstrating that ethylene regulates both adult Arabidopsis bolting and hypocotyls growth via ERF110 phsophorylation at Ser₅₃ position.