COP9 signalosome assembly

Definition

Target type: biologicalprocess

The aggregation, arrangement and bonding together of a set of components to form a COP9 signalosome. [PMID:17307927]

The COP9 signalosome (CSN) is a multi-protein complex that plays a crucial role in regulating protein degradation via the ubiquitin proteasome system (UPS). It is a highly conserved complex found in all eukaryotes, composed of eight subunits: CSN1, CSN2, CSN3, CSN4, CSN5, CSN6, CSN7, and CSN8. The assembly of this complex is a multi-step process that requires precise interactions between its subunits. Here's a breakdown of the steps involved:

**Step 1: Initial Assembly Core:**
- The assembly starts with the formation of a core complex composed of CSN1, CSN2, CSN3, and CSN5.
- CSN1 forms the central scaffold of the complex, interacting with CSN3 and CSN5.
- CSN2 binds to CSN3 and CSN5, further stabilizing the core structure.

**Step 2: Recruitment of CSN4 and CSN6:**
- The core complex then recruits CSN4 and CSN6.
- CSN4 binds to CSN1 and CSN5, while CSN6 interacts with both CSN1 and CSN4.
- This interaction results in a more stable and functional complex.

**Step 3: Addition of CSN7 and CSN8:**
- Finally, CSN7 and CSN8 join the complex.
- CSN7 interacts with both CSN1 and CSN2, while CSN8 associates with CSN5 and CSN6.
- The addition of CSN7 and CSN8 completes the fully assembled CSN complex.

**Assembly Regulation:**
- The assembly of the CSN complex is a tightly regulated process, influenced by various factors including:
- Cellular stress conditions
- Availability of specific substrates
- Interactions with other cellular proteins

**Importance of Proper Assembly:**
- The correct assembly of the CSN complex is crucial for its proper function.
- Misassembled CSN complexes can lead to dysregulation of protein degradation, contributing to various cellular malfunctions and diseases.
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Proteins (1)

Compounds (3)