Which of the following chemicalmessengerscommunicate with neighboring cells The Golgi apparatus is the primary organelle responsible for packaging peptide and protein messengers into secretory vesicles for release from eukaryotic cellsSecretion and Endocytosis - Scientific Foundations. This crucial step in the protein secretion pathway ensures that these vital molecules are correctly sorted, modified, and transported to their designated destinations, whether for internal use or release into the bloodstream or extracellular spaceThe Secretory Pathway: Randy Schekman.
Following synthesis on ribosomes and initial processing within the endoplasmic reticulum (ER), proteins destined for secretion are transported to the Golgi apparatus. Here, they undergo further modifications, such as glycosylation and proteolytic cleavage, as they move through the different compartments of the Golgi – the cis, medial, and trans cisternae. It is primarily within the trans Golgi network (TGN) that these proteins are sorted and concentrated, then bud off as secretory vesiclesGolgi Body - National Human Genome Research Institute (NHGRI). These vesicles act as transport carriers, holding their protein cargo until a specific signal triggers their fusion with the plasma membrane and the release of their contents via exocytosis.
The process of packaging proteins into secretory vesicles is a highly organized and sequential event involving several key cellular components.2023年6月19日—The Golgi apparatus packages peptide and protein messengers into secretory vesiclesin eukaryotic cells. It modifies, sorts, and sends these ...
1. Synthesis and Initial Folding in the ER: Peptide and protein messengers begin their journey as nascent polypeptide chains synthesized on ribosomes attached to the rough endoplasmic reticulum (ER). As they are synthesized, they enter the ER lumen, where they undergo folding, disulfide bond formation, and initial modifications like glycosylation, often aided by chaperone proteins. The ER also acts as a quality control checkpoint, ensuring only properly folded proteins proceed further.
2. Transport to the Golgi Apparatus: Properly folded proteins are then budded off from the ER in transport vesicles, which move towards and fuse with the cis face of the Golgi apparatus. These vesicles deliver their protein cargo to the earliest compartment of the Golgi.
3作者：E Crivellato·2008·被引用次数：100—Chromaffinvesicles(CV) are highly sophisticatedsecretory organellessynthesized in adrenal medullary chromaffin cells. They contain a complex mixture of structuralproteins, catecholamine neurotransmitters,peptidehormones, and the relative processing enzymes, as well as protease inhibitors.. Processing and Sorting in the Golgi: As proteins traverse through the stacked cisternae of the Golgi apparatus, they are further modified.作者：B Alberts·2002·被引用次数：14—Proteinsdestined forsecretory vesicles(called secretoryproteins) are packagedintoappropriate vesicles in the trans Golgi network by a mechanism that is ... Enzymes within the Golgi add or remove carbohydrate chains, cleave peptide bonds, and perform other post-translational modifications essential for the protein's final function and targeting作者：Z Hua·2013·被引用次数：10—Proteinsenter the Golgi by fusion of VTCs with a preexisting cis-most cisterna and exit from the TGN by being packagedintolargersecretory vesiclesfor .... The Golgi acts as a sophisticated sorting station, directing proteins to their correct final destinations.Golgi apparatus - Structure - Function - TeachMePhysiology
4. Packaging into Secretory Vesicles at the Trans Golgi Network (TGN): The trans Golgi network (TGN) is the final sorting and packaging hub. Here, proteins destined for secretion are segregated from those targeted for other organelles like lysosomes or the plasma membraneThe biogenesis ofsecretory vesiclesbegins with the synthesis of secretoryproteinsat the rough endoplasmic reticulum (RER), which are directedintothe RER .... They are then concentrated and bud off from the TGN as secretory vesicles.Proteins are sorted into the regulated secretory pathway in thetrans Golginetwork, where they are packaged into specialized secretory vesicles. These ... These vesicles can be either constitutive, releasing their contents continuously, or regulated, storing their cargo until a specific cellular signal initiates their fusion with the plasma membrane.
Secretory vesicles are diverse and can carry a variety of peptide and protein messengers.
* Hormones: Many peptide hormones, such as insulin, growth hormone, and oxytocin, are synthesized as prohormones, processed in the ER and Golgi, and stored in secretory vesicles for regulated release in response to physiological cues.The golgi apparatus packages materials into the secretory vesiclesfor storage and transportation. Neural or hormonal signals tell them when ...
* Neurotransmitters: While many neurotransmitters are small molecules, some neuropeptides function as neurotransmitters or neuromodulators and are packaged into secretory vesicles in neurons.
* Enzymes: Digestive enzymes and other extracellular enzymes are synthesized and secreted via secretory vesicles.
* Growth Factors and Cytokines: These signaling proteins involved in cell growth, differentiation, and immune responses are also packaged into secretory vesicles.
The packaging mechanism within the TGN is highly specific, ensuring that only the correct proteins are included in each type of secretory vesicle. This precision is critical for maintaining cellular communication and function.
Once formed, secretory vesicles are not static. They are often transported to specific regions of the cell, frequently along cytoskeletal tracks, to be poised for release. The fusion of these vesicles with the plasma membrane, a process known as exocytosis, is triggered by a variety of signals, including hormonal stimulation, neural impulses, or changes in intracellular calcium concentrations. This regulated release allows cells to respond rapidly and precisely to their environment, mediating complex biological processesWhich organelles contribute to synthesizing protein ....
In summary, the Golgi apparatus is indispensable for the cell's ability to communicate and function by packaging peptide and protein messengers into secretory vesicles. This intricate process, from ER synthesis to TGN packaging and final exocytosis, highlights the sophisticated machinery of cellular transport and secretion.
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