Ligand binding domain of steroid hormone receptors

The effector of the G αq/11 pathway is phospholipase C-β (PLCβ), which catalyzes the cleavage of membrane-bound phosphatidylinositol 4,5-biphosphate (PIP2) into the second messengers inositol (1,4,5) trisphosphate (IP3) and diacylglycerol (DAG). IP3 acts on IP3 receptors found in the membrane of the endoplasmic reticulum (ER) to elicit Ca 2+ release from the ER, DAG diffuses along the plasma membrane where it may activate any membrane localized forms of a second ser/thr kinase called protein kinase C (PKC). Since many isoforms of PKC are also activated by increases in intracellular Ca 2+ , both these pathways can also converge on each other to signal through the same secondary effector. Elevated intracellular Ca 2+ also binds and allosterically activates proteins called calmodulins , which in turn go on to bind and allosterically activate enzymes such as Ca 2+ /calmodulin-dependent kinases (CAMKs).

Evidence for crosstalk between the extrinsic and intrinsic pathways exists in the Fas signal cascade. In most cell types, caspase-8 catalyzes the cleavage of the pro-apoptotic BH3 -only protein Bid into its truncated form, tBid. BH-3 only members of the Bcl-2 family engage exclusively anti-apoptotic members of the family (Bcl-2, Bcl-xL), allowing Bak and Bax to translocate to the outer mitochondrial membrane, thus permeabilizing it and facilitating release of pro-apoptotic proteins such as cytochrome c and Smac/DIABLO , an antagonist of inhibitors of apoptosis proteins ( IAPs ).

Ligand binding domain of steroid hormone receptors

ligand binding domain of steroid hormone receptors

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ligand binding domain of steroid hormone receptorsligand binding domain of steroid hormone receptorsligand binding domain of steroid hormone receptorsligand binding domain of steroid hormone receptorsligand binding domain of steroid hormone receptors