Abstract
Tyrosine (Tyr) phosphorylation in protein is crucial to the control of growth and development of multicellular eukaryotes, including humans. In plant, the function of the Tyr phosphorylation has been largely neglected because a mammalian protein Tyr kinase homolog was not found. However, recent studies found protein Tyr phosphatase from Arabidopsis , and about 100 Tyr-phosphorylated proteins in Arabidopsis by MS-based phosphoproteomic screens. Thus plant might have Tyr phosphorylation network.In this study, by combining the wheat cell-free expression system and high-throughput detection system, AlphaScreen, we challenged to identify protein Tyr kinase and phosphorylation network in Arabidopsis plants. 759 Arabidopsis protein kinases in RAFL were synthesized and used for high-throughput profiling of serine/threonine/Tyr autophosphorylation activity. The results showed that 39 out of 759 protein kinases had the Tyr autophosphorylation activity, defined as plant protein Tyr kinases (PPTKs). New substrate proteins of PPTKs were also identified in protein library that Tyr phosphorylation has been reported. We will discuss their results.
