apelin receptor activity

Definition

Target type: molecularfunction

Combining with the peptide apelin to initiate a change in cell activity. [GOC:dph]

Apelin receptor activity encompasses the intricate molecular processes involved in mediating the biological effects of apelin, a potent bioactive peptide hormone, upon binding to its cognate G protein-coupled receptor (GPCR) known as the apelin receptor (APJ). This receptor activation triggers a cascade of intracellular signaling events that ultimately regulate various physiological functions, including cardiovascular homeostasis, metabolism, and neuroendocrine control. Upon apelin binding, the apelin receptor undergoes conformational changes, leading to the activation of heterotrimeric G proteins. These G proteins, primarily of the Gαq/11 subtype, dissociate into their α and βγ subunits, initiating distinct downstream signaling pathways. The activated Gαq/11 subunit stimulates phospholipase C (PLC), an enzyme that hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol (DAG) and inositol triphosphate (IP3). DAG activates protein kinase C (PKC), while IP3 triggers the release of calcium ions (Ca2+) from intracellular stores. The increased intracellular Ca2+ levels, along with the activation of PKC, contribute to a wide range of cellular responses, including smooth muscle contraction, vasoconstriction, and cell growth. Moreover, the βγ subunit of the activated G protein can directly interact with other signaling molecules, such as phosphoinositide 3-kinase (PI3K), to initiate additional downstream pathways. PI3K activation leads to the phosphorylation of Akt, a protein kinase involved in regulating cell survival, growth, and metabolism. Additionally, the apelin receptor can activate other signaling pathways independent of G protein coupling, such as the mitogen-activated protein kinase (MAPK) pathway. The activation of MAPK cascades is crucial for regulating cell proliferation, differentiation, and inflammation. In summary, apelin receptor activity involves a complex interplay of signaling pathways that ultimately mediate the diverse biological effects of apelin. These pathways converge on various downstream targets, including ion channels, protein kinases, and transcription factors, leading to the regulation of a wide range of cellular functions. The intricate nature of apelin receptor signaling highlights its importance in maintaining physiological homeostasis and its potential as a therapeutic target for various diseases.'
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Proteins (1)

Compounds (3)