Related Experiment Video
Updated: Jun 27, 2026
09:45
In Vitro SUMOylation Assay to Study SUMO E3 Ligase Activity
Published on: January 29, 2018
Protein Phosphatase 5 Promotes SUMM2-Mediated Immunity by Facilitating Its Protein Accumulation
Xingchuan Huang1, Yanan Liu2,3, Yuelin Zhang2,3
1Key Laboratory of Regional Characteristic Agricultural Resources, College of Life Sciences, Neijiang Normal University, Neijiang 641100, China.
Plants (Basel, Switzerland)
|June 26, 2026
Summary
Arabidopsis Protein Phosphatase 5 (PP5) is crucial for plant immunity, regulating the SUMM2 immune receptor. Loss of PP5 suppresses SUMM2-related autoimmune responses by stabilizing SUMM2 levels via HSP90.
Area of Science:
- Plant Biology
- Molecular Plant Pathology
- Immunology
Background:
- Protein Phosphatase 5 (PP5) is a conserved serine/threonine phosphatase with known roles in mammals.
- The function of PP5 in plants, particularly in immune processes, remains largely unexplored.
Purpose of the Study:
- To investigate the role of Arabidopsis PP5 in plant immunity.
- To elucidate the molecular mechanism by which PP5 influences the nucleotide-binding leucine-rich repeat (NLR) immune receptor SUMM2.
Main Methods:
- Genetic analysis of Arabidopsis pp5 loss-of-function mutants.
- Biochemical assays to determine protein-protein interactions (SUMM2, PP5, HSP90).
- Analysis of SUMM2 protein levels in wild-type and pp5 mutant plants.
Main Results:
- Arabidopsis PP5 is essential for immunity mediated by the SUMM2 immune receptor.
- pp5 mutations suppress autoimmune phenotypes triggered by SUMM2 activation.
- PP5 interacts with SUMM2 and Heat Shock Protein 90 (HSP90).
- PP5 deficiency leads to reduced SUMM2 protein levels, indicating a role in SUMM2 accumulation.
Conclusions:
- Arabidopsis PP5 plays a critical role in regulating plant immunity by stabilizing the SUMM2 immune receptor.
- PP5 likely promotes SUMM2 accumulation through its association with the HSP90 chaperone complex.
- These findings reveal a novel function for PP5 in plant defense signaling.
Related Concept Videos
01:20The JAK-STAT Signaling Pathway
Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as SH2...
01:25cAMP-dependent Protein Kinase Pathways
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
02:23Abnormal Proliferation
Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
01:22Amplifying Signals via Enzymatic Cascade
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
02:54Protein Kinases and Phosphatases
Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...