Modulation of TaALMTl Transport Activity by Protein Phosphorylation
Preincubation of Xenopus laevis oocytes expressing TaALMT1 (Al-activated malate transporter of wheat, Triticum aestivum) with inhibitors of protein kinases and phosphatases inactivated both the endogenous and Al-enhanced TaALMT1 currents ( malate efflux) suggesting the involvement of protein phosphorylation in TaALMT1 transport activity. A sequential deletion of predicted phosphorylation sites resulted in the loss of transport function of the protein except, surprisingly, for the deletion at the entire N-terminal half of the protein. The currents mediated by the N-terminal portion of the transporter, which harbors the membrane spanning domains, were not enhanced by Al as is seen in oocytes expressing the wildtype TaALMT1 protein. This result may indicate that the N-terminal half of the protein by itself can aggregate to form a pore that allows malate release without Al-activation, which may suggest that the Al-binding residue is located in the C-terminal domain. Further research is ongoing to analyze the structure and function of ALMT1-type proteins.
Ayalew Ligaba Miguel Pincros Leon V Kochian
USDA-ARS, Robert W.Holley Center for Agriculture and Health, Tower Road, Cornell University, ITHACA, NY, 14853-2901, USA
国际会议
The 7th International Symposium on Plant-Soil Interactions at Low pH(第七届低pH条件下植物-土壤交互作用国际研讨会)
广州
英文
73-74
2009-05-17（万方平台首次上网日期，不代表论文的发表时间）