positive regulation of cytoplasmic translation

Definition

Target type: biologicalprocess

Any process that activates or increases the frequency, rate or extent of cytoplasmic translation. [GOC:obol]

Positive regulation of cytoplasmic translation is a complex biological process that controls the rate at which proteins are synthesized in the cytoplasm. This process is essential for cellular function and is tightly regulated to ensure proper protein expression. Here is a detailed description:

**Initiation:**
- **Ribosome recruitment:** The process begins with the recruitment of ribosomes to mRNA molecules, which contain the genetic code for protein synthesis. This step involves a number of initiation factors (eIFs) that facilitate the binding of ribosomes to the 5' cap of the mRNA.
- **Scanning and AUG recognition:** Once bound, the ribosome scans the mRNA for the start codon (AUG). This codon signals the beginning of the protein-coding sequence.
- **tRNA binding:** The initiator tRNA, carrying the amino acid methionine, binds to the AUG codon. This event marks the initiation of protein synthesis.

**Elongation:**
- **Codon recognition and aminoacyl-tRNA binding:** The ribosome moves along the mRNA, reading each codon in turn. For each codon, the corresponding aminoacyl-tRNA, carrying the appropriate amino acid, binds to the A site of the ribosome.
- **Peptide bond formation:** Once bound, the amino acid on the aminoacyl-tRNA is linked to the growing polypeptide chain via a peptide bond, catalyzed by the ribosome.
- **Translocation:** The ribosome then translocates to the next codon, releasing the empty tRNA from the E site and bringing a new aminoacyl-tRNA into the A site. This cycle continues until the ribosome encounters a stop codon.

**Termination:**
- **Stop codon recognition:** When a stop codon is encountered, a release factor binds to the A site, triggering the release of the newly synthesized polypeptide chain from the ribosome.
- **Ribosome recycling:** The ribosome detaches from the mRNA and dissociates into its subunits, ready to initiate another round of translation.

**Regulation:**
- **Transcriptional control:** The rate of protein synthesis can be regulated at the level of transcription. This means that the amount of mRNA available for translation is controlled.
- **Translational control:** Regulation can also occur at the level of translation. This involves factors that affect the initiation, elongation, and termination of protein synthesis.
- **Post-translational modifications:** Once synthesized, proteins can undergo post-translational modifications that can affect their activity and stability.

**Key Factors in Positive Regulation:**
- **Initiation factors:** eIFs, particularly eIF4E, play a crucial role in the recruitment of ribosomes to the mRNA, initiating translation.
- **MicroRNAs:** These small RNA molecules can bind to mRNAs, preventing their translation.
- **Signal transduction pathways:** External signals can activate specific signaling pathways that ultimately lead to the regulation of translation.

**Examples of Positive Regulation:**
- **Cell growth and proliferation:** Translation is upregulated during cell growth and proliferation to synthesize the proteins needed for cell division.
- **Response to stress:** Stressful conditions can trigger an increase in translation of specific proteins that help the cell cope with the stress.
- **Development:** During development, translation is tightly regulated to ensure the proper expression of proteins required for different stages of development.

**Overall, positive regulation of cytoplasmic translation is a complex and essential process that ensures the precise synthesis of proteins required for cellular function and organismal development.**'"

Proteins (2)

Compounds (84)