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Ca(2+)-regulated serine protease associated with the nuclear scaffold
G A Clawson1, L L Norbeck, C L Hatem
1Department of Pathology and Biological Chemistry, Pennsylvania State University, Hershey 17033.
Cell Growth & Differentiation : the Molecular Biology Journal of the American Association for Cancer Research
|November 1, 1992
Summary
Researchers identified a novel serine protease that degrades nuclear lamins A/C, a key component of the nuclear scaffold. This protease activity is regulated by calcium ions and may control nuclear structure breakdown.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The nuclear scaffold (NS) maintains nuclear structure via intermediate filament proteins called lamins.
- Recent studies show lamins A/C are cleaved to form an ATP-binding protein by an NS protease.
- This protease is calcium-regulated and selective for lamins A/C.
Purpose of the Study:
- To identify the major protease responsible for nuclear scaffold breakdown.
- To characterize the properties and regulation of this NS protease.
- To explore the potential roles of this protease in nuclear structure dynamics and other cellular processes.
Main Methods:
- Protease activity assays using lamins A/C as substrates.
- Biochemical characterization of the protease, including substrate specificity and regulation by Ca2+.
- Comparison of the protease's properties to known proteinase complexes.
Main Results:
- Identified the major NS protease as a novel serine protease with chymotrypsin-like activity.
- Demonstrated that cytosolic Ca2+ perturbations significantly affect NS protease activity.
- Observed extensive similarities between this NS protease and the multicatalytic proteinase complex.
Conclusions:
- The novel serine protease plays a key role in nuclear scaffold breakdown.
- Calcium ions are critical regulators of NS protease activity.
- This protease may be involved in nuclear structure control during mitosis, disease, and regulation of oncogenic proteins.