User:Anthony Milto/Sandbox 1
From Proteopedia
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== Regulation == | == Regulation == | ||
| - | MyoD functions as a transcriptional activator only as a heterodimer with E proteins, which are a sub-family of bHLH proteins | + | MyoD is subject to regulation at both its bHLH domain and its acidic activation domain. MyoD functions as a transcriptional activator only as a heterodimer with E proteins, which are a sub-family of bHLH proteins. In one experiment, forced binding of E12 to MyoD that had been inhibited using E protein fragments robustly restored MyoD's activity [[5]]. Differences in E-box sequences and in complex formation determine the transcription factor's effect and allow differentiation into a diverse array of muscle cells [[2]]. The myogenic ability of MyoD is inhibited upon complex formation at the HLH domain with another bHLH protein known as Twist [[6]]. It has been proposed that DNA binding, with its accompanying structural changes, is required in vivo to free the acidic activation domain and activate MyoD's myogenic functions [[3]]. |
==DNA Interaction == | ==DNA Interaction == | ||
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[http://genesdev.cshlp.org/content/5/8/1377.long] | [http://genesdev.cshlp.org/content/5/8/1377.long] | ||
[http://genesdev.cshlp.org/content/11/4/436.full.pdf] | [http://genesdev.cshlp.org/content/11/4/436.full.pdf] | ||
| + | [http://genesdev.cshlp.org/content/23/6/694.full] | ||
| + | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC232510/ | ||
| + | |||
<references/> | <references/> | ||
Revision as of 01:57, 12 October 2015
Structure
MyoD, along with Myf5, is responsible for muscle cell differentiation and establishment of the myogenic lineage. It is a member of the basic helix loop helix (bHLH) family and myogenic factors subfamily of proteins1. MyoD has a basic region at its amino-terminal end, which functions in binding the transcription factor to a region of the DNA known as the E-box. At the carboxyl-terminal end is MyoD's HLH domain. The HLH domain functions in protein-protein interactions and forms homodimeric and heterodimeric complexes 2. MyoD also contains an acidic activation domain. The activity of this activation domain has been observed to increase drastically upon deletion of residues in other parts of the protein. This suggests that the acidic activation domain is buried within the protein in vivo and can be activated by subtle changes in structure 3. MyoD's ability to activate endogenous genes has been shown to rely on two regions. The first is a region rich in cysteine and histidine residues that is between the acidic activation domain and the bHLH domain. The second is a region near the carboxyl terminus of the protein. These regions are conserved in proteins with shared functionality 4.
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References
[1] [2] [3] [4] [5] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC232510/
- ↑ Hanson, R. M., Prilusky, J., Renjian, Z., Nakane, T. and Sussman, J. L. (2013), JSmol and the Next-Generation Web-Based Representation of 3D Molecular Structure as Applied to Proteopedia. Isr. J. Chem., 53:207-216. doi:http://dx.doi.org/10.1002/ijch.201300024
- ↑ Ma PC, Rould MA, Weintraub H, Pabo CO. Crystal structure of MyoD bHLH domain-DNA complex: perspectives on DNA recognition and implications for transcriptional activation. Cell. 1994 May 6;77(3):451-9. PMID:8181063
