Submitted:
09 May 2026
Posted:
11 May 2026
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Abstract
Protein Phosphatase 5 (PP5) is an evolutionarily conserved serine/threonine phosphatase with a unique tetratricopeptide domain. It has been implicated in a wide range of cellular processes in mammals, but its function in plants is unknown. Here we uncovered that Arabidopsis PP5 is required for immunity mediated by the nucleotide-binding leucine-rich repeat immune receptor protein SUMM2. Loss-of-function mutations in PP5 suppress the autoimmune phenotypes caused by the activation of SUMM2 due to the disruption of the MEKK1-MKK1/MKK2-MPK4 kinase cascade. Further biochemical analysis revealed that SUMM2 interacts with Heat Shock Protein 90 and PP5, and SUMM2 level is reduced in pp5 knockout mutant plants, suggesting that PP5 functions as a co-chaperone to regulate the accumulation of SUMM2.
Keywords:
protein phosphatase 5 (PP5)
; SUMM2
; HSP90
; co-chaperone
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