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The mitotic checkpoint protein hBUB3 and the mRNA export factor hRAE1 interact with GLE2p-binding sequence
1Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
The Journal of Biological Chemistry
|May 16, 2001
Summary
The mRNA export factor RAE1 and mitotic checkpoint protein BUB3 share homology. Their interaction sites, GLEBS motifs, are found in nucleoporins and checkpoint proteins, binding RAE1, BUB3, or both.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- The mRNA export factor RAE1 (also called GLE2) and the mitotic checkpoint protein BUB3 exhibit sequence homology across species.
- Previous studies identified the GLEBS motif in hNUP98 as a binding site for hRAE1.
Purpose of the Study:
- To investigate the biological relevance of RAE1 and BUB3 sequence homology.
- To identify and characterize the binding interactions between RAE1, BUB3, and their respective partners.
Main Methods:
- Sequence homology analysis.
- Protein binding assays (GLEBS-like motif interactions).
- Co-immunoprecipitation and immunofluorescence in mammalian cells.
Main Results:
- BUB3 binding partners (BUB1, BUBR1) possess GLEBS-like motifs, distinct from the NUP98 GLEBS.
- BUB3 specifically binds to GLEBS motifs on BUB1/BUBR1, not NUP98.
- RAE1 can bind both NUP98 GLEBS and BUB1 GLEBS motifs.
- RAE1 and BUB1 interact in mammalian cells and localize to kinetochores.
Conclusions:
- GLEBS motifs are present in both nucleoporins and mitotic checkpoint proteins.
- These GLEBS motifs serve as specific binding sites for BUB3, RAE1, or both.
- RAE1 and BUB1 proteins interact and function at kinetochores during mitosis.
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