An atypical dual-specificity protein tyrosine phosphatase PFA-DSP3 is
involved in plant salt response through modulating MPK3 and MPK6
Protein phosphorylation, especially serine/threonine and tyrosine
phosphorylation, plays significant roles in signaling processes during
plant growth and development as well as their responses to biotic or
abiotic stresses. The dual-specificity protein tyrosine phosphatases are
important to de-phosphorylate and inactivate the signaling components.
In this study, we reported an atypical dual specificity protein tyrosine
phosphatase ATPFA-DSP3 (DSP3), which loss-of-function mutant was
insensitive to salt treatment, played a negative role in plant’s
response to salinity in Arabidopsis. DSP3 protein was primarily
localized in nuclei and degraded after salt treatment. The level of ROS
accumulation was lower in dsp3 mutant and higher in DSP3 over-expresser
than wild type control, indicating DSP3 positively affect ROS
production. DSP3 can directly interact with MPK3 and MPK6, and the
phosphorylated MPK3 and MPK6 over accumulate in dsp3 mutant. Moreover,
the phosphatase activity of DSP3 was required for its salt response.
These results provide evidences showing that DSP3 negatively mediates
plant salt response by directly modulating the accumulation of
phosphorylated MPK3 and MPK6.