UBIQUITIN-SPECIFIC PROTEASE16 interacts with a HEAVY METAL ASSOCIATED ISOPRENYLATED PLANT PROTEIN27 and modulates cadmium tolerance.

Protein ubiquitination and deubiquitination are two reversible processes catalyzed by ubiquitin ligases and deubiquitinating enzymes, respectively. In Arabidopsis, lots of substrates of ubiquitin ligases were found, whereas only a few targets of deubiquitinating enzymes were identified. Recently, we reported that a functional UBIQUITIN-SPECIFIC PROTEASE16 (UBP16) was involved in salt tolerance through positively regulating plasma membrane Na+/H+ antiport activity and at least partially modulating SERINE HYDROXYMETHYLTRANSFERASE1 (SHM 1) stability and activity. Here, we report that UBP16 interacts with HEAVY META L ASSOCIATED ISOPRENYLATED PLANT PROTEIN 27 (HI PP27), a metallochaperone containing a predicted heavy-metal-associated domain, which has been reported to play an important role in cadmium detoxification. Meanwhile, the ubp16 mutant showed more sensitive to cadmium than wild-type. Taken together, HI PP27 may be another target of UBP16 in cadmium response.