signaling receptor ligand precursor processing

Definition

Target type: biologicalprocess

The cleavage of a peptide bond in a precursor form of a signaling receptor ligand, resulting in the mature (active) form of the ligand. [PMID:29247995]

Signaling receptor ligand precursor processing is a complex biological process that involves the synthesis, modification, and activation of signaling molecules, known as ligands, which bind to specific receptors on target cells. The process can be divided into several key steps:

1. Gene Transcription and Translation: The process begins with the transcription of the gene encoding the ligand precursor protein. This DNA sequence is copied into messenger RNA (mRNA), which is then translated into a polypeptide chain. The polypeptide chain is the primary structure of the protein and is often called a pre-proprotein.

2. Signal Peptide Cleavage: The pre-proprotein typically contains a signal peptide, a short amino acid sequence that directs the protein to the endoplasmic reticulum (ER). The signal peptide is cleaved off by a signal peptidase enzyme during or shortly after translocation into the ER lumen. This cleavage generates the proprotein, which now lacks the signal peptide and is ready for further processing.

3. Protein Folding and Glycosylation: Within the ER lumen, the proprotein undergoes folding into its correct three-dimensional structure, guided by chaperone proteins. This folding process is crucial for the protein's activity and stability. Additionally, many ligand precursors are glycosylated, meaning that sugar molecules are added to specific amino acid residues. Glycosylation can influence protein folding, stability, and biological activity.

4. Transport to Golgi Apparatus: Following folding and glycosylation, the proprotein is transported from the ER to the Golgi apparatus, a series of membrane-bound compartments that further process and sort proteins.

5. Post-translational Modifications: Within the Golgi, the proprotein undergoes further post-translational modifications, which may include additional glycosylation, phosphorylation, sulfation, or proteolytic cleavage. These modifications contribute to the final maturation and activation of the ligand.

6. Packaging and Sorting: As the ligand precursor progresses through the Golgi, it is packaged into vesicles for transport to its final destination. Depending on the specific ligand and its target cell, this destination may be the cell surface, secretory granules, or lysosomes.

7. Ligand Activation: The final activation step for the ligand often occurs after its release from the cell. This activation can involve proteolytic cleavage, phosphorylation, or other modifications that expose the binding site for the receptor.

8. Receptor Binding and Signal Transduction: Once activated, the ligand binds to its specific receptor on the target cell, initiating a cascade of events that ultimately alter cellular function. This signaling pathway can lead to a variety of responses, including changes in gene expression, cell growth, differentiation, or even cell death.

The processing of signaling receptor ligand precursors is a highly regulated and complex process, ensuring that the correct ligand is produced, activated, and delivered to its target cell at the appropriate time. Dysregulation of this process can contribute to a variety of diseases.'
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Proteins (2)

Compounds (158)