regulation of protein secretion

Definition

Target type: biologicalprocess

Any process that modulates the frequency, rate or extent of the controlled release of a protein from a cell. [GOC:ai]

Protein secretion is a fundamental cellular process that involves the movement of proteins from the inside of a cell to the outside. It is a tightly regulated process, ensuring that the correct proteins are secreted at the appropriate time and in the appropriate amounts.

The process begins in the ribosomes, where proteins are synthesized. Ribosomes translate mRNA into proteins, and the newly synthesized proteins are targeted to the endoplasmic reticulum (ER) via a signal peptide. This signal peptide is a short sequence of amino acids that directs the ribosome and the nascent protein to the ER membrane.

Once at the ER, the signal peptide is cleaved by a signal peptidase, and the protein enters the ER lumen. Here, proteins undergo folding and post-translational modifications, such as glycosylation. The ER serves as a quality control checkpoint, ensuring that only properly folded proteins are allowed to proceed to the next step.

From the ER, proteins are transported to the Golgi apparatus, a series of flattened membrane-bound sacs. In the Golgi, proteins are further modified and sorted. They may be glycosylated, sulfated, or phosphorylated. The Golgi also plays a role in the packaging of proteins into transport vesicles.

These vesicles bud off from the Golgi and transport the proteins to their final destinations. For proteins destined for secretion, the vesicles fuse with the plasma membrane, releasing the proteins into the extracellular space.

Regulation of protein secretion occurs at multiple steps.

At the transcriptional level, the expression of genes encoding secretory proteins is tightly controlled. This involves the binding of transcription factors to specific DNA sequences in the promoter regions of these genes.

At the translational level, the rate of protein synthesis is regulated by factors such as the availability of mRNA, the activity of ribosomes, and the presence of chaperone proteins.

At the post-translational level, protein secretion is regulated by the activity of chaperone proteins, which help to fold and transport proteins through the secretory pathway.

The process of protein secretion is also regulated by various signaling pathways, including the unfolded protein response (UPR). The UPR is a cellular stress response that is activated when there is an accumulation of unfolded or misfolded proteins in the ER. The UPR leads to the upregulation of genes involved in protein folding, degradation, and secretion.

Overall, the regulation of protein secretion is a complex and highly coordinated process. It is essential for maintaining cellular homeostasis and for carrying out various physiological functions, including cell signaling, cell-cell interactions, and immune responses.'
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Proteins (1)

Compounds (9)