S100 protein binding

Definition

Target type: molecularfunction

Binding to a S100 protein. S100 is a small calcium and zinc binding protein produced in astrocytes that is implicated in Alzheimer's disease, Down Syndrome and ALS. [GOC:jid]

S100 proteins are a family of small, calcium-binding proteins that play a crucial role in diverse cellular processes, including calcium signaling, cell growth, differentiation, and inflammation. Their molecular function is centered around their ability to bind calcium ions and then interact with various target proteins, modulating their activity.

Here's a detailed breakdown of their molecular function:

1. **Calcium Binding:** S100 proteins possess two EF-hand motifs, which are helix-loop-helix structures that bind calcium ions. Upon calcium binding, they undergo a conformational change, exposing a hydrophobic surface crucial for protein-protein interactions.

2. **Target Protein Recognition:** The calcium-bound S100 proteins interact with their target proteins through specific protein-protein interactions. These interactions are highly regulated and often dependent on the presence of calcium and the cellular context.

3. **Modulation of Target Protein Activity:** Once bound to their targets, S100 proteins can modulate their activity in several ways:
* **Activation:** They can promote the activity of their target proteins by acting as molecular chaperones, facilitating their correct folding or assembly.
* **Inhibition:** They can suppress the activity of their targets by blocking their active sites or interacting with regulatory domains.
* **Localization:** They can alter the subcellular localization of their targets, thereby influencing their function.

4. **Diversity of Target Proteins:** S100 proteins interact with a wide range of target proteins, including:
* **Transcription factors:** Regulating gene expression.
* **Enzymes:** Influencing metabolic pathways.
* **Cytoskeletal proteins:** Altering cell morphology and motility.
* **Signaling proteins:** Modulating signal transduction pathways.

5. **Role in Cellular Processes:** S100 protein binding is essential for a myriad of cellular functions, including:
* **Calcium signaling:** Transducing calcium signals into cellular responses.
* **Cell growth and differentiation:** Regulating cell cycle progression and specialization.
* **Inflammation:** Mediating immune responses and inflammatory processes.
* **Neurotransmission:** Modulating synaptic plasticity and neuronal function.

6. **Disease Relevance:** Dysregulation of S100 protein binding has been implicated in various human diseases, including cancer, neurodegenerative disorders, and autoimmune diseases.

Overall, S100 protein binding is a complex and multifaceted process that plays a vital role in maintaining cellular homeostasis and orchestrating a wide range of cellular functions.'
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Proteins (7)

Compounds (30)