vesicle docking involved in exocytosis

Definition

Target type: biologicalprocess

The initial attachment of a vesicle membrane to a target membrane, mediated by proteins protruding from the membrane of the vesicle and the target membrane, that contributes to exocytosis. [GOC:aruk, GOC:bc, GOC:jid, PMID:22438915]

Vesicle docking is a crucial step in exocytosis, the process by which cells release molecules to the extracellular space. It involves a complex series of interactions between the vesicle membrane and the target membrane, ultimately leading to their fusion. The process can be broken down into several key stages:

1. **Tethering:** Vesicles initially approach the target membrane through interactions with tethering proteins. These proteins act like molecular "ropes" that bridge the gap between the vesicle and the target membrane. Examples of tethering proteins include the golgin family of proteins, which bind to both vesicle and target membranes, and the exocyst complex, which facilitates vesicle docking at the plasma membrane.

2. **Docking:** Once tethered, the vesicle docks at the target membrane. This involves the formation of a tight interaction between the vesicle and target membranes, mediated by a specialized set of proteins called SNAREs. SNAREs are transmembrane proteins that exist in two forms: v-SNAREs (found on vesicles) and t-SNAREs (found on target membranes).

3. **SNARE Complex Formation:** v-SNAREs and t-SNAREs interact with each other to form a stable SNARE complex. This complex draws the vesicle and target membrane together, bringing them into close proximity for fusion.

4. **Fusion:** The final stage of vesicle docking involves the merging of the vesicle and target membranes, resulting in the release of the vesicle's contents into the extracellular space. This process requires the removal of water molecules between the two membranes and is thought to involve a protein called synaptotagmin, which acts as a calcium sensor.

The specific mechanisms involved in vesicle docking can vary depending on the type of vesicle and the target membrane. However, the general principles of tethering, docking, SNARE complex formation, and fusion are common to all forms of exocytosis.'
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Proteins (2)

Compounds (14)