Protein Tyrosine Phosphorylation during Phytohormone-Stimulated Cell Proliferation in Arabidopsis Hypocotyls

Abstract

;Very little is known about the molecular events triggering differentiated cells to re-enter the cell cycle. We have investigated the possible role of tyrosine phosphorylation in this process with hypocotyl explants of Arabidopsis thaliana. Phytohormone-stimulated cell cycle reactivation in hypocotyls was accompanied by tyrosine phosphorylation of several proteins. Such regulation of the tyrosine phosphorylation in these proteins was not observed in a callusformation-deficient mutant, srd2, a result which suggests that the induction of tyrosine phosphorylation occurs as a specific event in callus cell proliferation. The promoter activity of cyclin-dependent kinase, CDKA;1, was also examined in phytohormone-stimulated hypocotyls. This study highlighted that protein tyrosine phosphorylation may play an important regulatory role in phytohormonestimulated cell proliferation.

ArabidopsisPASTICCINO2 Is an Antiphosphatase Involved in Regulation of Cyclin-Dependent Kinase A

“…Nonetheless, several PTPs and kinases have been described in Arabidopsis Xu et al, 1998;Fordham-Skelton et al, 1999Ulm et al, 2001Ulm et al, , 2002. Tyr phosphorylation has also been involved in several physiological responses, such as bending or phytohormone-stimulated cell proliferation (Kameyama et al, 2000;Huang et al, 2003). We show here that the level of CDKA;1 Tyr phosphorylation is controlled by PAS2.…”

Protein Tyrosine Kinases and Protein Tyrosine Phosphatases Are Involved in Abscisic Acid-Dependent Processes in Arabidopsis Seeds and Suspension Cells

“…Therefore, this kind of posttranslational modification may play an important role in seeds. Similar approaches based on immunodetection have demonstrated the role of Tyr phosphorylation in pulvinus movement in M. pudica and hypocotyl growth in Arabidopsis (Kameyama et al, 2000;Huang et al, 2003). Tyr phosphorylation of at least 19 seed proteins was modulated after ABA treatment: eight were Tyr dephosphorylated and 11 were Tyr phosphorylated (Fig.…”

“…Although the role of protein Tyr phosphorylation in plant physiology is less documented than for animals (Hunter, 1998), there is evidence for their involvement. Tyr phosphorylated proteins have been detected in carrot (Daucus carota) cells, Mimosa pudica leaves, Arabidopsis hypocotyls, and Arabidopsis suspension cells (Barizza et al, 1999;Kameyama et al, 2000;Huang et al, 2003;Sugiyama et al, 2008). In addition, Tyr phosphorylation modulates embryogenesis in coconut (Cocos nucifera), and copper modulates Tyr phosphorylation of proteins in rice (Oryza sativa) roots (Islas-Flores et al, 1998;Hung et al, 2007).…”

Signal processing by protein tyrosine phosphorylation in plants

“…23 Immunoblotting with anti-phospho-Tyr antibodies have permitted detection of plant proteins phosphorylated on Tyr in several other species. 17,19,[24][25][26][27][28][29][30][31][32][33][34][35][36][37] Involvement of PTKs and PTPs by pharmacological approaches. One way to probe specifically elements of signal transduction pathways is by perturbating these pathways through the loss of function of one of these elements.…”