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Updated: Oct 4, 2025

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Published on: January 17, 2025
Lamina-associated polypeptide 2α is required for intranuclear MRTF-A activity.
Ekaterina Sidorenko1, Maria Sokolova1, Antti P Pennanen1
1Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
Lamina-associated polypeptide 2α (Lap2α) is a novel nuclear regulator of Myocardin-related transcription factor A (MRTF-A). Lap2α is essential for MRTF-A/SRF target gene expression and serum-induced cell migration.
Area of Science:
- Molecular Biology
- Cell Biology
- Transcriptional Regulation
Background:
- Myocardin-related transcription factor A (MRTF-A) is a key coactivator of serum response factor (SRF).
- MRTF-A regulates cytoskeletal gene expression in response to actin dynamics.
- Existing regulators of MRTF-A primarily act by controlling its nuclear localization.
Purpose of the Study:
- To identify novel mechanisms regulating MRTF-A activity within the nucleus.
- To investigate the role of lamina-associated polypeptide 2α (Lap2α) in MRTF-A-mediated transcription.
- To elucidate the functional consequences of Lap2α-MRTF-A interaction.
Main Methods:
- Co-immunoprecipitation assays to confirm MRTF-A and Lap2α binding.
- Quantitative PCR and Western blotting to assess gene expression.
- Cell migration assays to evaluate phenotypic effects.
- Chromatin immunoprecipitation to analyze histone modifications.
Main Results:
- Lap2α directly binds to MRTF-A within the nucleus.
- Lap2α is required for efficient recruitment of MRTF-A to its target genes, independent of nuclear localization.
- Lap2α's function precedes MRTF-A chromatin binding and does not directly affect histone marks.
- Loss of Lap2α impairs serum-induced cell migration and may influence muscle and proliferation phenotypes.
Conclusions:
- Lap2α represents a novel nuclear regulator of MRTF-A activity.
- Lap2α facilitates MRTF-A/SRF target gene expression by promoting MRTF-A recruitment, not localization.
- This study expands the known functions of Lap2α in transcriptional regulation and highlights a new layer of control for MRTF-A-SRF signaling.
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