Search results
Results from the WOW.Com Content Network
The intrinsic pathway of apoptosis (also known as the mitochondrial pathway, intracellular pathway, or intrinsic apoptosis), cell death initiated by changes in mitochondria. The intrinsic pathway of blood coagulation (also known as the contact activation pathway), a cascade of enzymatic reactions resulting in blood clotting.
The intrinsic pathway is activated by intracellular signals generated when cells are stressed and depends on the release of proteins from the intermembrane space of mitochondria. [20] The extrinsic pathway is activated by extracellular ligands binding to cell-surface death receptors, which leads to the formation of the death-inducing signaling ...
Further, the final common pathway scheme implies that prothrombin is converted to thrombin only when acted upon by the intrinsic or extrinsic pathways, which is an oversimplification. In fact, thrombin is generated by activated platelets at the initiation of the platelet plug, which in turn promotes more platelet activation.
Intrinsic tenase complex contains the active factor IX (IXa), its cofactor factor VIII (VIIIa), the substrate (factor X), and they are activated by negatively charged surfaces (such as glass, active platelet membrane, sometimes cell membrane of monocytes).
This intrinsic pathway involves the release of cytochrome C from the mitochondria and subsequent binding to the cytosolic protein Apaf-1. [ 16 ] [ 17 ] Cytochrome c release is thus necessary for the initiation of apoptosome action; this release is regulated in a number of ways, most importantly by detection of calcium ion levels.
Blood coagulation pathways in vivo showing the central role played by thrombin. Factor Xa is the activated form of the coagulation factor X, also known as thrombokinase. Factor X is an enzyme, a serine endopeptidase, which plays a key role at several stages of the coagulation system. Factor X is synthesized in the liver.
HMWK is one of four proteins which interact to initiate the contact activation pathway (also called the intrinsic pathway) of coagulation: the other three are Factor XII, Factor XI and prekallikrein. HMWK is not enzymatically active, and functions only as a cofactor for the activation of kallikrein and factor XII. It is also necessary for the ...
The neurotrophic theory is the leading hypothesis used to explain the role of programmed cell death in the developing nervous system. [31] It postulates that in order to ensure optimal innervation of targets, a surplus of neurons is first produced which then compete for limited quantities of protective neurotrophic factors and only a fraction ...