seven-transmembrane G protein-coupled receptor superfamily; This hierarchical evolutionary model represents the seven-transmembrane (7TM) receptors, often referred to as G protein-coupled receptors (GPCRs), which transmit physiological signals from the outside of the cell to the inside via G proteins. GPCRs constitute the largest known superfamily of transmembrane receptors across the three kingdoms of life that respond to a wide variety of extracellular stimuli including peptides, lipids, neurotransmitters, amino acids, hormones, and sensory stimuli such as light, smell and taste. All GPCRs share a common structural architecture comprising of seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops. A general feature of GPCR signaling is agonist-induced conformational changes in the receptors, leading to activation of the heterotrimeric G proteins, which consist of the guanine nucleotide-binding G-alpha subunit and the dimeric G-beta-gamma subunits. The activated G proteins then bind to and activate numerous downstream effector proteins, which generate second messengers that mediate a broad range of cellular and physiological processes. However, some 7TM receptors, such as the type 1 microbial rhodopsins, do not activate G proteins. Based on sequence similarity, GPCRs can be divided into six major classes: class A (the rhodopsin-like family), class B (the Methuselah-like, adhesion and secretin-like receptor family), class C (the metabotropic glutamate receptor family), class D (the fungal mating pheromone receptors), class E (the cAMP receptor family), and class F (the frizzled/smoothened receptor family). Nearly 800 human GPCR genes have been identified and are involved essentially in all major physiological processes. Approximately 40% of clinically marketed drugs mediate their effects through modulation of GPCR function for the treatment of a variety of human diseases including bacterial infections.

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gi 2120575619   1 PIIYCRSPDFRKAF 14
Cdd:cd15058   292 PIIYCRSPEFRTAF 305

beta adrenergic receptors (adrenoceptors), member of the class A family of seven-transmembrane G protein-coupled receptors; The beta adrenergic receptor (beta adrenoceptor), also known as beta AR, is activated by hormone adrenaline (epinephrine) and plays important roles in regulating cardiac function and heart rate, as well as pulmonary physiology. The human heart contains three subtypes of the beta AR: beta-1 AR, beta-2 AR, and beta-3 AR. Beta-1 AR and beta-2 AR, which expressed at about a ratio of 70:30, are the major subtypes involved in modulating cardiac contractility and heart rate by positively stimulating the G(s) protein-adenylate cyclase-cAMP-PKA signaling pathway. In contrast, beta-3 AR produces negative inotropic effects by activating inhibitory G(i) proteins. The aberrant expression of beta-ARs can lead to cardiac dysfunction such as arrhythmias or heart failure. All GPCRs have a common structural architecture comprising of seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops. A general feature of GPCR signaling is agonist-induced conformational changes in the receptors, leading to activation of the heterotrimeric G proteins, which consist of the guanine nucleotide-binding G-alpha subunit and the dimeric G-beta-gamma subunits. The activated G proteins then bind to and activate numerous downstream effector proteins, which generate second messengers that mediate a broad range of cellular and physiological processes.

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gi 2120575619   1 PIIYCRSPDFRKAF 14
Cdd:cd15058   292 PIIYCRSPEFRTAF 305

beta adrenergic receptors (adrenoceptors), member of the class A family of seven-transmembrane G protein-coupled receptors; The beta adrenergic receptor (beta adrenoceptor), also known as beta AR, is activated by hormone adrenaline (epinephrine) and plays important roles in regulating cardiac function and heart rate, as well as pulmonary physiology. The human heart contains three subtypes of the beta AR: beta-1 AR, beta-2 AR, and beta-3 AR. Beta-1 AR and beta-2 AR, which expressed at about a ratio of 70:30, are the major subtypes involved in modulating cardiac contractility and heart rate by positively stimulating the G(s) protein-adenylate cyclase-cAMP-PKA signaling pathway. In contrast, beta-3 AR produces negative inotropic effects by activating inhibitory G(i) proteins. The aberrant expression of beta-ARs can lead to cardiac dysfunction such as arrhythmias or heart failure. All GPCRs have a common structural architecture comprising of seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops. A general feature of GPCR signaling is agonist-induced conformational changes in the receptors, leading to activation of the heterotrimeric G proteins, which consist of the guanine nucleotide-binding G-alpha subunit and the dimeric G-beta-gamma subunits. The activated G proteins then bind to and activate numerous downstream effector proteins, which generate second messengers that mediate a broad range of cellular and physiological processes.

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                  ....*....|....
gi 2120575619   1 PIIYCRSPDFRKAF 14
Cdd:cd15058   292 PIIYCRSPEFRTAF 305

beta-3 adrenergic receptors (adrenoceptors), member of the class A family of seven-transmembrane G protein-coupled receptors; The beta-3 adrenergic receptor (beta-3 adrenoceptor), also known as beta-3 AR, is activated by adrenaline and plays important roles in regulating cardiac function and heart rate. The human heart contains three subtypes of the beta AR: beta-1 AR, beta-2 AR, and beta-3 AR. Beta-1 AR and beta-2 AR, which expressed at about a ratio of 70:30, are the major subtypes involved in modulating cardiac contractility and heart rate by positively stimulating the G(s) protein-adenylate cyclase-cAMP-PKA signaling pathway. In contrast, beta-3 AR produces negative inotropic effects by activating inhibitory G(i) proteins. The aberrant expression of betrayers can lead to cardiac dysfunction such as arrhythmias or heart failure.

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gi 2120575619   1 PIIYCRSPDFRKAF 14
Cdd:cd15959   289 PIIYCRSPDFRSAF 302