Related Experiment Videos
Identification of three major sentrinization sites in PML
T Kamitani1, K Kito, H P Nguyen
1Division of Molecular Medicine, Department of Internal Medicine, The University of Texas-Houston Health Science Center, Houston, TX 77030, USA.
The Journal of Biological Chemistry
|October 3, 1998
Summary
Sentrinization, a protein modification, regulates nuclear body formation in wild type PML. This process is disrupted in acute promyelocytic leukemia, but can be restored by sentrin overexpression.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Acute promyelocytic leukemia (APL) is linked to the PML-RARalpha fusion protein.
- Wild-type PML undergoes sentrinization, a modification absent in PML-RARalpha.
Purpose of the Study:
- To identify the specific sites of PML sentrinization.
- To elucidate the role of sentrinization in PML localization and nuclear body formation.
- To understand the regulation of PML-RARalpha sentrinization in APL.
Main Methods:
- Extensive mutational analysis of PML protein.
- Site-directed mutagenesis to substitute lysine residues with arginine.
- Subcellular localization studies using microscopy.
- Investigating the effect of sentrin overexpression and retinoic acid treatment.
Main Results:
- Identified Lys65 (RING finger), Lys160 (B1 Box), and Lys490 (nuclear localization signal) as major PML sentrinization sites.
- A triple mutant (Lys to Arg at these sites) showed no sentrinization and predominantly nucleoplasmic localization, unlike wild-type PML in nuclear bodies.
- Sentrinization of PML-RARalpha was restored by sentrin overexpression, not retinoic acid.
Conclusions:
- Sentrinization of PML, involving the RING finger and B1 box, is crucial for nuclear body formation.
- The findings offer new insights into the pathobiology of APL and the function of the sentrinization pathway.