Importance of tyrosine phosphorylation for transmembrane signaling in plants

Abstract

Reversible protein phosphorylation is a widespread post-translational modification fundamental for signaling across all domains of life. Tyrosine (Tyr) phosphorylation has recently emerged as being important for plant receptor kinase (RK)-mediated signaling, particularly during plant immunity. How Tyr phosphorylation regulates RK function is however largely unknown. Notably, the expansion of protein Tyr phosphatase and SH2 domain-containing protein families, which are the core of regulatory phospho-Tyr (pTyr) networks in choanozoans, did not occur in plants. Here, we summarize the current understanding of plant RK Tyr phosphorylation focusing on the critical role of a pTyr site (‘VIa-Tyr’) conserved in several plant RKs. Furthermore, we discuss the possibility of metazoan-like pTyr signaling modules in plants based on atypical components with convergent biochemical functions.

Potato protein tyrosine phosphatase StPTP1a is activated by StMKK1 to negatively regulate plant immunity

“…Although there are no typical tyrosine kinases identified in plants, some plant RLKs are capable of tyrosine phosphorylation (Bojar et al, 2014). Phospho-proteomics data show that the relative abundance of phosphorylated tyrosine residues in plants is similar to that in animals (Ahsan et al, 2020;M€ uhlenbeck et al, 2021), hereby indicating the important role that tyrosine phosphorylation plays in signalling events in plants. Thus, the role of plant PTPs is probably largely underestimated, and furthermore, how plant PTPs are actually activated remains unknown.…”

Importance of Tyrosine Phosphorylation in Hormone-Regulated Plant Growth and Development

“…All the identified 57 kinases possess both the Ser/Thr-specificity motifs in subdomains VI and the Tyr-specificity motifs in subdomain XI, suggesting that all of these kinases belong to a DsPTK family [ 8 ]. Recent studies have shown that many important plant receptor-like kinases (RLKs), sharing similar architectures with metazoan RTKs, exhibited the dual-specificity kinase activities, indicating that the Tyr phosphorylation is also an important regulatory mechanism in plants [ 19 , 26 ]. A recent in silico analysis in rice genome developed by Allimuthu et al identified 18 DsPTKs which share >80% identity within the conserved sequences of subdomains VI, VIII, and XI with the Arabidopsis Brassinosteroid-Insensitive1 (BRI1) [ 27 ], a cell surface-localized leucine-rich repeat (LRR) RLK that functions as the BR receptor [ 28 ].…”

“…The “writer” and “eraser” functions are fulfilled by DsPTKs and PTPs/DUSPs in plant cells, respectively. It was well-known that the “reader” proteins in mammals can specifically recognize and bind certain pTyr residues on target proteins to propagate the phosphorylation in a wide range of signaling pathways [ 19 ]. It would be a challenging task to find plant-specific “reader” proteins or “reader” motifs important to regulate many phosphorylation-mediated signaling processes in plants.…”

“…Recent studies have also suggested an important regulatory function of Tyr phosphorylation in the signaling processes of other plant hormones [ 16 , 17 , 18 ]. Furthermore, Tyr phosphorylation was also found to play crucial roles in plant stress tolerance, including the pathogens’ induced immunity and resistance to abiotic stresses such as drought and salinity [ 9 , 19 , 20 ]. However, our short review only covers the studies that demonstrated important regulatory functions of the Tyr phosphorylation in the signaling pathways of phytohormones-mediated plant growth and development, with a general discussion on protein kinases and phosphatases that are either specific to Tyr residue or exhibit dual specificity toward Ser/Thr and Tyr residues.…”

S-Nitrosation of Arabidopsis thaliana Protein Tyrosine Phosphatase 1 Prevents Its Irreversible Oxidation by Hydrogen Peroxide

“…All PTPases possess a signature motif of 11 amino acids at the active site (I/V)HCXAGXXR(S/T)G, which contains the cysteine (Cys) catalytic residue (indicated in bold) involved in the formation of a phosphoenzyme intermediate during the reaction (Guan and Dixon, 1991). Tyr phosphorylation and consequently Tyr dephosphorylation have recently emerged as important mechanisms for transmembrane signaling in plants, in particular in immunity processes (Mühlenbeck et al, 2021).…”