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Published on: May 17, 2016
Differential localization of HDAC4 orchestrates muscle differentiation
1Wellcome/CRC Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK.
Nucleic Acids Research
|August 16, 2001
Summary
Histone deacetylase 4 (HDAC4) is crucial for muscle differentiation, relocating to the nucleus post-fusion to regulate gene expression. Calcium signaling prevents its nuclear entry, inhibiting muscle development.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Class II histone deacetylases, HDAC4 and HDAC5, interact with the MEF2 transcription factor, repressing its activity.
- HDAC4's role in muscle differentiation is suggested, but its precise localization and regulation remain unclear.
Purpose of the Study:
- To investigate the intracellular localization and regulatory mechanisms of HDAC4 during myoblast differentiation.
- To elucidate the role of the Ca(2+)/calmodulin signaling pathway in controlling HDAC4 activity and muscle differentiation.
Main Methods:
- Immunofluorescence microscopy to track HDAC4 localization during myoblast differentiation.
- Overexpression studies to assess the impact of aberrant HDAC4 localization on myogenic gene expression.
- Biochemical assays to examine the interaction of HDAC4 with 14-3-3 proteins and the role of phosphorylation.
Main Results:
- HDAC4 is predominantly cytoplasmic during early myoblast differentiation and translocates to the nucleus upon cell fusion.
- Overexpression of HDAC4 in the nucleus suppresses myogenic gene expression and MEF2-dependent transcription.
- Activation of the Ca(2+)/calmodulin pathway via CaMKIV prevents nuclear entry of HDAC4, thereby inhibiting its suppressive effects on differentiation.
- HDAC4 binds to 14-3-3 proteins in a phosphorylation-dependent manner, suggesting a mechanism for its cytoplasmic retention.
Conclusions:
- HDAC4 plays a critical role in regulating muscle differentiation through its dynamic intracellular localization.
- Phosphorylation-dependent binding to 14-3-3 proteins sequesters HDAC4 in the cytoplasm, while nuclear translocation is linked to differentiation.
- The Ca(2+)/calmodulin pathway modulates HDAC4 localization and activity, highlighting its importance in controlling muscle development.
- Opposed localization of HDAC4 and HDAC5 suggests distinct, yet coordinated, roles in muscle differentiation.
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