protein transmembrane import into intracellular organelle
Definition
Target type: biologicalprocess
The directed movement of proteins into an intracellular organelle, across a membrane. [GOC:jl]
Protein transmembrane import into intracellular organelles is a fundamental process in cellular biology, ensuring the proper localization and function of proteins within different compartments. This intricate process involves a series of steps, starting with the synthesis of the protein on ribosomes and culminating in its delivery to the target organelle.
Here's a detailed description:
1. **Signal Peptide Recognition:** The journey begins with the synthesis of a protein destined for an organelle. Such proteins typically possess a signal peptide, a short amino acid sequence at the N-terminus that acts as a "zip code," directing the protein to its correct destination. The signal peptide interacts with a signal recognition particle (SRP), a cytosolic ribonucleoprotein complex.
2. **SRP-Ribosome Binding and Targeting to the Translocon:** The SRP, carrying the ribosome-bound nascent polypeptide, interacts with the SRP receptor on the organelle's membrane. This interaction triggers the recruitment of the ribosome to the translocon, a protein channel embedded in the membrane.
3. **Translocation through the Translocon:** Once docked at the translocon, the nascent polypeptide begins its journey across the membrane. The signal peptide enters the translocon first, followed by the rest of the polypeptide chain. The translocon acts as a gatekeeper, allowing passage only to the target protein.
4. **Signal Peptide Cleavage:** As the protein translocates, the signal peptide is often cleaved off by a signal peptidase enzyme located in the organelle lumen. This cleavage event is crucial for the proper folding and function of the protein within the target compartment.
5. **Folding and Chaperone Assistance:** Once inside the organelle, the translocated protein folds into its native three-dimensional structure. This process can be aided by chaperone proteins, which prevent misfolding and aggregation.
6. **Organelle-Specific Sorting:** Some proteins destined for specific intracellular organelles, such as the Golgi apparatus or the endoplasmic reticulum, might require additional sorting signals or chaperone interactions to ensure their proper delivery.
7. **Post-Translational Modifications:** Many proteins undergo post-translational modifications, such as glycosylation or phosphorylation, after reaching their destination, which further contribute to their function and stability.
In summary, protein transmembrane import is a complex process that involves a series of well-coordinated steps, ensuring the efficient and precise delivery of proteins to their appropriate intracellular locations, ultimately contributing to the proper functioning of the cell.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Heat shock cognate 71 kDa protein | A heat shock cognate 71 kDa protein that is encoded in the genome of human. [PRO:DAN] | Homo sapiens (human) |
Compounds (9)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| adenosine diphosphate | Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position. | adenosine 5'-phosphate; purine ribonucleoside 5'-diphosphate | fundamental metabolite; human metabolite |
| tubercidin | tubercidin : An N-glycosylpyrrolopyrimidine that is adenosine in which the in the 5-membered ring that is not attached to the ribose moiety is replaced by a carbon. Tubercidin is produced in the culture broth of Streptomyces tubericidus. Tubercidin: An antibiotic purine ribonucleoside that readily substitutes for adenosine in the biological system, but its incorporation into DNA and RNA has an inhibitory effect on the metabolism of these nucleic acids. | antibiotic antifungal agent; N-glycosylpyrrolopyrimidine; ribonucleoside | antimetabolite; antineoplastic agent; bacterial metabolite |
| toyocamycin | toyocamycin : An N-glycosylpyrrolopyrimidine that is tubercidin in which the hydrogen at position 5 of the pyrrolopyrimidine moiety has been replaced by a cyano group. Toyocamycin: 4-Amino-5-cyano-7-(D-ribofuranosyl)-7H- pyrrolo(2,3-d)pyrimidine. Antibiotic antimetabolite isolated from Streptomyces toyocaensis cultures. It is an analog of adenosine, blocks RNA synthesis and ribosome function, and is used mainly as a tool in biochemistry. | antibiotic antifungal agent; N-glycosylpyrrolopyrimidine; nitrile; ribonucleoside | antimetabolite; antineoplastic agent; apoptosis inducer; bacterial metabolite |
| nsc 65346 | sangivamycin : A nucleoside analogue that is adenosine in which the nitrogen at position 7 is replaced by a carbamoyl-substituted carbon. It is a potent inhibitor of protein kinase C. sangivamycin: RN given refers to parent cpd | nucleoside analogue | protein kinase inhibitor |
| adenosine | quinquefolan B: isolated from roots of Panax quinquefolium L.; RN not in Chemline 10/87; RN from Toxlit | adenosines; purines D-ribonucleoside | analgesic; anti-arrhythmia drug; fundamental metabolite; human metabolite; vasodilator agent |
| 8-aminoadenosine | |||
| 5'-deoxyadenosine | 5'-deoxyadenosine : A 5'-deoxyribonucleoside compound having adenosine as the nucleobase. 5'-deoxyadenosine: main heading DEOXYADENOSINE refers to the 3' cpd | 5'-deoxyribonucleoside; adenosines | Escherichia coli metabolite; human metabolite; mouse metabolite |
| ver 155008 | VER 155008: structure in first source | purine nucleoside | |
| nms-e973 | NMS-E973: structure in first source |