Related Experiment Video
Updated: Jun 6, 2026
09:45
In Vitro SUMOylation Assay to Study SUMO E3 Ligase Activity
Published on: January 29, 2018
Control of nuclear HIPK2 localization and function by a SUMO interaction motif
Laureano de la Vega1, Katrin Fröbius, Rita Moreno
1Institute of Biochemistry, Medical Faculty, Friedrichstrasse 24, Justus-Liebig-University, 35392 Giessen, Germany.
Biochimica Et Biophysica Acta
|December 15, 2010
Summary
The SUMO interaction motif (SIM) in HIPK2 is crucial for its localization in nuclear speckles and interaction with other proteins. This SUMO binding regulates HIPK2
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- The serine/threonine kinase HIPK2 plays a role in gene expression, differentiation, and cell death.
- HIPK2's localization within subnuclear speckles is essential for its function but the underlying structural mechanisms were unclear.
Purpose of the Study:
- To identify the structural components responsible for HIPK2's localization in subnuclear speckles.
- To investigate the role of SUMOylation and SUMO-binding motifs in HIPK2 localization and function.
Main Methods:
- Point mutation analysis was employed to map key functional regions within HIPK2.
- SUMO-binding assays and co-immunoprecipitation were used to study protein interactions.
- Immunofluorescence microscopy was utilized to visualize HIPK2 localization in cells.
Main Results:
- Two nuclear localization signals and a SUMO interaction motif (SIM) were identified in HIPK2.
- The SIM binds SUMO-1, SUMO-2, and SUMO-3, with SUMO-1 mediating covalent conjugation.
- Mutation or deletion of the SIM disrupted HIPK2 localization to nuclear speckles and impaired interactions with PML and Pc2, affecting HIPK2's kinase activity.
Conclusions:
- The SUMO interaction motif (SIM) is critical for HIPK2's subnuclear localization and its interactions with PML and Pc2.
- SUMOylation, particularly non-covalent SIM-SUMO interactions, acts as a molecular glue, enhancing protein-protein interactions and regulating HIPK2 function.
- Understanding SUMO/SIM interactions provides insights into the regulation of kinase activity and protein complex formation within nuclear speckles.
More Related Videos
Related Concept Videos
01:45Regulation of Nuclear Protein Sorting
Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
01:46Nuclear Localization Signals and Import
Proteins targeted to the nucleus carry short stretches of amino acid sequences called the nuclear localization signal or NLS. Classical nuclear localization signals are of two types: monopartite and bipartite NLS. Monopartite classical NLS (cNLS) consists of a single cluster of 4-8 amino acids. Bipartite cNLS consists of two clusters of 2-3 amino acids and a 9-12 residue long proline-rich linker bridging the two clusters. Signal clusters are rich in positively charged amino acids such as...
02:53Conservative Site-specific Recombination and Phase Variation
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
01:42Nuclear Export
The nucleus restricts several proteins within and allows others to pass. The restricted proteins possess a nuclear retention sequence or NRS, anchoring them to the nuclear lamins and preventing their transport to the cytosol. The non-restricted proteins, after their synthesis, are transported to their site of action, such as the cytosol or other organelles, with the help of nuclear export signals or NES.
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
01:34Nuclear Protein Sorting
Nuclear protein sorting is the selective trafficking of histones, polymerases, gene regulatory proteins into the nucleus and exporting RNAs and ribosomes to the cytosol. It is a tightly controlled process that regulates gene expression within a cell.
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.