Srp-dependent Pathway
Srp-dependent Pathway - Related Videos
02:26
NF-kB-dependent Signaling Pathway
0 Views •
2023
The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals. NF-κB-dependent Signaling Mechanism The heterodimer of NF-κB...
02:26
NF-κB-dependent Signaling Pathway
0 Views •
2021
The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals. NF-κB-dependent Signaling Mechanism The heterodimer of NF-κB...
01:25
cAMP-dependent Protein Kinase Pathways
0 Views •
2023
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
03:17
Temperature Dependence - Concepts
0 Views •
2020
Chemical Kinetics The reaction rate is the speed at which a chemical reaction occurs. The reaction rate is defined as the change in concentration of a component in the reaction with time. The speed of a reaction depends on several factors, including the concentration of reactants and the temperature at which the reaction is performed. Each reactant contributes to the speed of the reaction by a specific factor. This relationship is defined by the reaction rate law. Rate Law The rate law is an...
01:27
C4 Pathway and CAM
0 Views •
2019
Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative pathways to fix carbon and conserve energy loss due to photorespiration. Photorespiration is the process that occurs when the oxygen concentration is high. Under such conditions, the rubisco enzyme in the Calvin cycle binds O2 instead of CO2, which halts photosynthesis and consumes energy. C4 Pathway The C4 pathway is used by plants such as...
FAQs
The hydrophobic signal sequence acts as the recognition feature exposed by the growing nascent chain. Once it emerges from the ribosome, SRP binds both the sequence and the ribosome, creating a targeted complex rather than allowing the chain to proceed without membrane-directed handling. This couples signal detection to delivery.
Temporary slowing of translation creates time for targeting before synthesis proceeds too far. Because the ribosome pauses after SRP binds the nascent chain, the complex can engage the SRP receptor and be transferred to a protein-conducting channel. Resumption at the membrane coordinates continued synthesis with entry or integration of the protein.
The SRP receptor provides the membrane-associated docking step between the SRP-bound ribosome and the protein-conducting channel. After the SRP-ribosome complex engages this receptor, the ribosome is transferred toward the channel, such as Sec61 in the endoplasmic reticulum. This handoff positions ongoing protein synthesis at the correct membrane site.
After transfer to the protein-conducting channel, translation resumes while the growing protein moves into or integrates into the membrane. These two outcomes allow the same targeting sequence to support different localization results: some proteins enter the membrane-associated transport route, whereas others become organized within the membrane itself. The outcome helps establish correct cellular protein placement.
The sequence begins when a hydrophobic signal emerges from the ribosome. SRP then binds the signal and ribosome, temporarily slowing translation. The complex engages the SRP receptor on the target membrane, and the ribosome is transferred to a protein-conducting channel. Translation resumes there, allowing the protein to enter or integrate into the membrane.
The pathway supports the production and localization of secreted and membrane proteins. By directing nascent proteins to membranes, it contributes to secretion, membrane organization, and correct protein localization. In the endoplasmic reticulum, the Sec61 translocon provides an example of the channel through which this membrane-associated delivery can proceed.