SIGNAL SEQUENCE Meaning and
Definition
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A signal sequence is a segment of amino acids that directs the transport of new proteins to specific locations within a cell or to the cell's exterior. It is typically found at the N-terminus, which is the starting end of a polypeptide chain. The signal sequence acts like a molecular address label, ensuring that the protein is delivered to the appropriate destination.
During protein synthesis, ribosomes initially attach to the mRNA molecule and begin translating the genetic code into a polypeptide chain. As the emerging protein is synthesized, the signal sequence emerges first and is recognized by a signal recognition particle (SRP). This interaction temporarily stalls translation until the ribosome-SRP complex attaches to a receptor on the endoplasmic reticulum (ER). Once attached, the protein synthesis resumes, and the growing polypeptide chain is threaded through a protein channel into the ER lumen, leaving the signal sequence behind in the membrane.
Signal sequences can vary in length and composition, but they share common features that enable recognition by the SRP and subsequent targeting to the ER or other organelles. These features often include a positively charged region followed by a hydrophobic stretch, as well as other amino acids that help in fine-tuning the protein's destination.
Overall, signal sequences play a crucial role in cellular trafficking and ensure proteins are correctly sorted to their intended locations, allowing them to perform their specific functions within the cell.
Common Misspellings for SIGNAL SEQUENCE
- aignal sequence
- zignal sequence
- xignal sequence
- dignal sequence
- eignal sequence
- wignal sequence
- sugnal sequence
- sjgnal sequence
- skgnal sequence
- sognal sequence
- s9gnal sequence
- s8gnal sequence
- sifnal sequence
- sivnal sequence
- sibnal sequence
- sihnal sequence
- siynal sequence
- sitnal sequence
- sigbal sequence
- sigmal sequence
Etymology of SIGNAL SEQUENCE
The word "signal sequence" has a fairly straightforward etymology. It combines the noun "signal" and the noun "sequence".
1. Signal: The word "signal" dates back to the late 15th century and has its origins in the Old French word "signale", meaning "sign, mark, or signature". It later evolved from the Latin word "signum" meaning "mark" or "token". In the context of biology, a signal is an event or cue that triggers a specific response or action.
2. Sequence: The word "sequence" comes from the Latin word "sequentia", meaning "a following" or "a succession". It entered the English language in the early 15th century, referring to an ordered arrangement or succession of elements.
When these two words are combined to form "signal sequence", it refers to a specific ordered arrangement or succession of amino acids within a protein.
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