PMID:20561251

Citation	Park, HC, Kim, H, Koo, SC, Park, HJ, Cheong, MS, Hong, H, Baek, D, Chung, WS, Kim, DH, Bressan, RA, Lee, SY, Bohnert, HJ and Yun, DJ (2010) Functional characterization of the SIZ/PIAS-type SUMO E3 ligases, OsSIZ1 and OsSIZ2 in rice. Plant Cell Environ. 33:1923-34
Abstract	Sumoylation is a post-translational regulatory process in diverse cellular processes in eukaryotes, involving conjugation/deconjugation of small ubiquitin-like modifier (SUMO) proteins to other proteins thus modifying their function. The PIAS [protein inhibitor of activated signal transducers and activators of transcription (STAT)] and SAP (scaffold attachment factor A/B/acinus/PIAS)/MIZ (SIZ) proteins exhibit SUMO E3-ligase activity that facilitates the conjugation of SUMO proteins to target substrates. Here, we report the isolation and molecular characterization of Oryza sativa SIZ1 (OsSIZ1) and SIZ2 (OsSIZ2), rice homologs of Arabidopsis SIZ1. The rice SIZ proteins are localized to the nucleus and showed sumoylation activities in a tobacco system. Our analysis showed increased amounts of SUMO conjugates associated with environmental stresses such as high and low temperature, NaCl and abscisic acid (ABA) in rice plants. The expression of OsSIZ1 and OsSIZ2 in siz1-2 Arabidopsis plants partially complemented the morphological mutant phenotype and enhanced levels of SUMO conjugates under heat shock conditions. In addition, ABA-hypersensitivity of siz1-2 seed germination was partially suppressed by OsSIZ1 and OsSIZ2. The results suggest that rice SIZ1 and SIZ2 are able to functionally complement Arabidopsis SIZ1 in the SUMO conjugation pathway. Their effects on the Arabidopsis mutant suggest a function for these genes related to stress responses and stress adaptation.
Links	PubMed Online version:10.1111/j.1365-3040.2010.02195.x
Keywords	Abscisic Acid/pharmacology; Amino Acid Sequence; Arabidopsis/genetics; Cell Nucleus/metabolism; Gene Expression Regulation, Plant; Genetic Complementation Test; Hot Temperature; Molecular Sequence Data; Oryza sativa/enzymology; Oryza sativa/genetics; Plant Proteins/genetics; Plant Proteins/metabolism; Plants, Genetically Modified/enzymology; Plants, Genetically Modified/genetics; RNA, Plant/genetics; Sequence Homology, Amino Acid; Small Ubiquitin-Related Modifier Proteins/genetics; Small Ubiquitin-Related Modifier Proteins/metabolism; Stress, Physiological; Sumoylation; Tobacco/metabolism; Ubiquitin-Protein Ligases/genetics; Ubiquitin-Protein Ligases/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ORYSJ:SIZ1		GO:0061665: SUMO ligase activity	ECO:0000314:		F		Figure 5 shows when SIZ1 is expressed with AtSUMO1, sumoylation in high molecular weight range increases. This indicates SIZ1 may act as an E3 ligase.	complete CACAO 10415
ORYSJ:SIZ1		GO:0016925: protein sumoylation	ECO:0000314:		P		Inferred from Figure 5, when SIZ1 expressed with AtSUMO1 sumoylation in high molecular weight range increased.	complete CACAO 10419
ORYSJ:SIZ1	enables	GO:0061665: SUMO ligase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
ORYSJ:SIZ1	involved_in	GO:0016925: protein sumoylation	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
ORYSJ:SIZ2	enables	GO:0061665: SUMO ligase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
ORYSJ:SIZ2	involved_in	GO:0016925: protein sumoylation	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
ORYSJ:SIZ2		GO:0061665: SUMO ligase activity	ECO:0000314:		F		Figure 5 shows when SIZ2 expressed with AtSUMO1, sumoylation in high molecular weight range increases. This indicates SIZ2 may act as an E3 ligase.	complete CACAO 10417
ORYSJ:SIZ2		GO:0016925: protein sumoylation	ECO:0000314:		P		Inferred from Figure5, when SIZ2 expressed with AtSUMO1 sumoylation in high molecular weight range increased	complete CACAO 10418

References

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