title: Inside job: ligand-receptor pharmacology beneath the plasma membrane.
abstract: Most drugs acting on the cell surface receptors are membrane permeable and thus able to engage their target proteins in different subcellular compartments. However, these drugs' effects on cell surface receptors have historically been studied on the plasma membrane alone. Increasing evidence suggests that small molecules may also modulate their targeted receptors through membrane trafficking or organelle-localized signaling inside the cell. These additional modes of interaction have been reported for functionally diverse ligands of GPCRs, ion channels, and transporters. Such intracellular drug-target engagements affect cell surface expression. Concurrent intracellular and cell surface signaling may also increase the complexity and therapeutic opportunities of small molecule modulation. Here we discuss examples of ligand-receptor interactions that are present in both intra- and extracellular sites, and the potential therapeutic opportunities presented by this phenomenon.
authors.affiliation: Solomon H. Snyder Department of Neuroscience, High Throughput Biology Center and Johns Hopkins Ion Channel Center, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Babcock
authors.forename: Min
authors.initials: M
authors.lastname: Li
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D045604:Extracellular Fluid / Q000378:metabolism; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism; D008024:Ligands; D021381:Protein Transport / Q000502:physiology; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D007473:Ion Channels; D008024:Ligands; D011956:Receptors, Cell Surface