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Differential regulation of sentrinized proteins by a novel sentrin-specific protease
1Research Center for Cardiovascular Diseases, Institute of Molecular Medicine for the Prevention of Human Diseases, Division of Molecular Medicine, The University of Texas-Houston Health Science, Houston, USA.
The Journal of Biological Chemistry
|February 1, 2000
Summary
A novel protease, SENP1, specifically cleaves sentrin-1 (SUMO-1) and sentrin-2 conjugates, but not ubiquitin or NEDD8. This nuclear-localized enzyme selectively processes sentrinized PML, offering insights into its role in cancer.
Area of Science:
- Molecular Biology
- Biochemistry
- Cell Biology
Background:
- Sentrin-1 (SUMO-1) is a ubiquitin-like protein involved in post-translational modification.
- De-ubiquitinating enzymes (DUBs) and ubiquitin C-terminal hydrolases (UCHs) are known enzymes that process ubiquitin and related proteins.
- The specific proteases for sentrin family proteins were largely uncharacterized.
Purpose of the Study:
- To identify and characterize a novel protease specific for sentrin proteins.
- To investigate the in vivo activity and substrate specificity of the identified protease.
- To explore the potential role of this protease in regulating sentrinization of specific proteins, such as PML.
Main Methods:
- Cloning and expression of a novel protease, SENP1, in a COS cell system.
- Co-expression of HA-tagged sentrin-1 with SENP1 to assess in vivo activity.
- Analysis of SENP1 activity against various sentrinized and ubiquitinated proteins, including PML and RanGAP1.
- In vitro assays to confirm SENP1 activity against sentrinized RanGAP1.
Main Results:
- SENP1 efficiently removes high molecular weight sentrin-1 conjugates in vivo, increasing free sentrin-1 monomers.
- SENP1 is active against sentrin-2 conjugates but not ubiquitin or NEDD8 conjugates.
- SENP1 selectively processes sentrinized PML but not sentrinized RanGAP1 in vivo, likely due to its nuclear localization.
- SENP1 demonstrates in vitro activity against sentrinized RanGAP1.
Conclusions:
- SENP1 is a novel, nuclear-localized, sentrin-specific protease.
- SENP1 plays a role in regulating sentrinization, particularly affecting nuclear proteins like PML.
- SENP1 provides a valuable tool for studying sentrinization in biological processes and diseases like acute promyelocytic leukemia.