Mad-Max complex

Definition

Target type: cellularcomponent

A transcriptional repressor complex that consists of a heterodimer of the bHLH-ZIP proteins Mad and Max. [PMID:8224841]

The Mad-Max complex is a multi-protein complex involved in mRNA degradation in eukaryotes. Its cellular component is primarily localized to cytoplasmic processing bodies (P-bodies), which are dynamic ribonucleoprotein (RNP) granules that function as sites for mRNA decay, storage, and translation repression. The P-bodies are characterized by their dense and granular appearance under electron microscopy and are enriched in a variety of proteins involved in mRNA metabolism, including decapping enzymes, 5' to 3' exonucleases, deadenylases, and translation initiation factors.

The Mad-Max complex is composed of several core components, including:

* **The CCR4-NOT complex:** This large, multi-subunit complex is a major regulator of mRNA deadenylation and degradation. The CCR4-NOT complex contains several enzymatic activities, including deadenylase, ubiquitin ligase, and histone acetyltransferase activities.
* **The PAN2-PAN3 complex:** This heterodimer acts as a 3' to 5' exonuclease that degrades the poly(A) tail of mRNAs.
* **The DCP2 decapping enzyme:** This enzyme removes the 5' cap from mRNAs, which is a critical step in mRNA degradation.
* **Other proteins:** The Mad-Max complex also includes other proteins involved in mRNA metabolism, such as the translation initiation factor eIF4E, the mRNA-binding protein Lsm1, and the helicase Dhh1.

The assembly of the Mad-Max complex within P-bodies is a dynamic process that is regulated by various cellular signals. The complex plays a critical role in the post-transcriptional regulation of gene expression by controlling the stability and translation of mRNAs. This regulation is essential for cellular processes such as development, differentiation, and stress response.'
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Proteins (1)

Compounds (2)