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Alternative splicing of the mouse profilin II gene generates functionally different profilin isoforms
A Di Nardo1, R Gareus, D Kwiatkowski
1EMBL-Monterotondo, Mouse Biology Programme, Via Ramarini 32, Rome, Italy.
Journal of Cell Science
|October 18, 2000
Summary
Mouse profilin II gene generates two isoforms, IIA and IIB, through alternative splicing. Profilin IIA interacts with actin, while IIB binds to tubulin, suggesting diverse roles in cytoskeletal dynamics.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Profilins are essential proteins regulating actin dynamics and cell motility.
- Two profilin genes exist in mice: profilin I (ubiquitous) and profilin II (brain-specific).
Purpose of the Study:
- To investigate the diversity of mouse profilin II by identifying and characterizing its isoforms.
- To elucidate the distinct functional roles of these profilin II isoforms in cellular processes.
Main Methods:
- Analysis of alternative splicing to identify profilin II isoforms.
- Protein binding assays (poly-L-proline, actin, tubulin).
- In vivo imaging of GFP-tagged profilin IIB during mitosis in HeLa cells.
Main Results:
- Two mouse profilin II isoforms, IIA and IIB, arise from alternative splicing, differing in their C-terminal sequences.
- Profilin IIA exhibits high affinity for actin and poly-L-proline, similar to profilin I.
- Profilin IIB shows reduced affinity for poly-L-proline and does not bind actin, but interacts with tubulin and localizes to mitotic spindles.
Conclusions:
- Mouse profilin II exhibits functional divergence through its isoforms.
- Profilin IIA plays a role in actin dynamics, whereas profilin IIB associates with tubulin and the mitotic apparatus.
- This study reveals unexpected functional diversity within the profilin protein family.