platelet dense tubular network

Definition

Target type: cellularcomponent

A network of membrane-bounded compartments found in blood platelets, where they regulate platelet activation by sequestering or releasing calcium. The dense tubular network exists as thin elongated membranes in resting platelets, and undergoes a major ultrastructural change, to a rounded vesicular form, upon addition of thrombin. [PMID:1322202]

The platelet dense tubular network (DTN) is a specialized intracellular organelle unique to platelets, a type of blood cell crucial for hemostasis (blood clotting). This network is characterized by a complex interconnected system of tubules and vesicles, resembling a labyrinthine structure. Its primary function is to store and release bioactive molecules, primarily serotonin, ADP, and calcium ions, during platelet activation. These molecules are essential for recruiting additional platelets to the site of injury, initiating the coagulation cascade, and promoting platelet aggregation, thus forming a stable plug to stop bleeding. The DTN is tightly regulated, maintaining a specific equilibrium between storage and release of its contents. Its formation is dependent on the cytoskeletal network within platelets, particularly actin and myosin, which contribute to the tubule formation and organization. Additionally, the DTN is closely associated with the platelet alpha-granules, another type of organelle containing various clotting factors and proteins. During activation, the DTN releases its contents via exocytosis, facilitated by the fusion of the DTN tubules with the platelet plasma membrane. This orchestrated release ensures a rapid and efficient response to injury, effectively initiating the critical process of hemostasis.'
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Proteins (2)

Compounds (16)