cell surface receptor signaling pathway via STAT

Definition

Target type: biologicalprocess

An intracellular signal transduction process in which STAT proteins (Signal Transducers and Activators of Transcription) convey a signal to trigger a change in the activity or state of a cell. The STAT cascade begins with receptor activation followed by activation of STAT proteins by kinases. It proceeds through STA dimerization and subsequent nuclear translocation of STAT proteins, and ends with regulation of target gene expression by STAT proteins. [GOC:rjd, PMID:21534947, PMID:24587195]

Cell surface receptor signaling pathway via STAT is a complex process that involves a cascade of molecular events initiated by the binding of a ligand to a cell surface receptor. This pathway is crucial for various cellular functions, including cell growth, differentiation, survival, and immune responses.

Here's a detailed description of the key steps involved:

1. **Ligand Binding and Receptor Dimerization:** The process begins with the binding of a specific ligand to its cognate cell surface receptor. This binding event triggers a conformational change in the receptor, leading to its dimerization. This means that two receptor molecules come together to form a complex.

2. **Activation of Tyrosine Kinases:** Many cell surface receptors involved in STAT signaling are receptor tyrosine kinases (RTKs). Upon ligand binding, the associated tyrosine kinases become activated. These kinases phosphorylate tyrosine residues on the receptor itself and on other signaling proteins, creating docking sites for downstream signaling molecules.

3. **Recruitment of STAT Proteins:** Phosphorylated tyrosine residues on the activated receptor provide docking sites for specific proteins called signal transducers and activators of transcription (STATs). STATs are a family of transcription factors that play a central role in this pathway.

4. **STAT Dimerization and Phosphorylation:** Once recruited to the receptor, STAT proteins become phosphorylated on specific tyrosine residues by the activated tyrosine kinases. This phosphorylation event is essential for STAT activation. Phosphorylated STAT proteins then dimerize, forming a stable dimer complex.

5. **Nuclear Translocation and Gene Transcription:** The STAT dimers, now activated, translocate from the cytoplasm into the nucleus. In the nucleus, they bind to specific DNA sequences called STAT response elements (REs) located in the regulatory regions of target genes. Binding of the STAT dimer to the REs initiates transcription of these genes, leading to the synthesis of new proteins that contribute to the cellular response.

6. **Termination of Signaling:** The STAT signaling pathway is tightly regulated to ensure a precise and timely response. Several mechanisms contribute to the termination of signaling, including:
- Dephosphorylation of STAT proteins by phosphatases, leading to their inactivation.
- Degradation of STAT proteins via proteasomal pathways.
- Negative feedback loops involving other signaling molecules.

7. **Diverse Cellular Responses:** The activation of specific STAT proteins and the downstream genes they regulate lead to a wide range of cellular responses. For instance, STAT1 activation is often associated with immune responses, while STAT3 activation can promote cell growth and survival. The specific cellular outcome depends on the type of ligand, the activated receptor, the STAT proteins involved, and the target genes regulated.

In summary, cell surface receptor signaling pathway via STAT is a complex and highly regulated process that plays a critical role in cellular communication and function. The pathway involves a series of molecular events, from ligand binding to gene transcription, ultimately leading to diverse cellular responses.'
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Proteins (1)

Compounds (28)