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Shuttling of SOX proteins
Safia Malki1, Brigitte Boizet-Bonhoure, Francis Poulat
1Carnegie Institution, Department of Embryology, Baltimore, MD, USA.
The International Journal of Biochemistry & Cell Biology
|October 8, 2009
Summary
SOX proteins control gene expression via nuclear localization signals (NLSs) and nuclear export signals within their HMG domain. These signals regulate SOX protein activity, influencing dynamic cellular events and development.
Area of Science:
- Molecular Biology
- Developmental Biology
- Genetics
Background:
- SOX proteins regulate gene expression by controlling access to nuclear targets.
- Sub-cellular targeting sequences, including nuclear localization signals (NLSs) and nuclear export signals, are concentrated in the HMG domain of SOX proteins.
Purpose of the Study:
- To investigate the role and regulation of NLSs and nuclear export signals in SOX protein function.
- To understand how these signals influence SOX protein activity and nucleocytoplasmic shuttling.
Main Methods:
- Analysis of SOX protein domains, specifically the HMG box.
- Identification and characterization of N-terminal and C-terminal NLSs and their binding partners (calmodulin, importin-beta).
- Examination of nuclear export signals in different SOX protein groups and during mouse embryonic development.
Main Results:
- SOX proteins possess distinct NLSs (N-terminal binding calmodulin, C-terminal binding importin-beta) and a nuclear export signal within the HMG domain.
- Mutations in SRY's NLSs cause developmental disorders like sex reversal, highlighting the importance of functional NLSs.
- Group E SOX proteins have a consensus nuclear export signal, while others may also be regulated by nuclear export, suggesting dynamic nucleocytoplasmic shuttling.
Conclusions:
- SOX protein activity is tightly regulated by the interplay of NLSs and nuclear export signals.
- The nucleocytoplasmic shuttling properties of SOX proteins indicate highly dynamic cellular events controlled by these factors.
- Understanding SOX protein localization is crucial for comprehending developmental processes and associated disorders.
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