Application Methods: Immunofluorescence (Frozen), Immunoprecipitation, Western Blotting
Background: The μ-opioid receptor (MOR) belongs to the superfamily of G-protein-coupled receptors. MOR mediates the analgesic and rewarding effects of morphine and other opiates as well as the actions of several endogenous opioid peptides (1). Upon binding to its ligands, this Gi-coupled receptor inactivates adenylyl cyclase (1) and activates a variety of G-beta-gamma-dependent pathways including the MAPK and the PI3K/Akt cascades (2,3). Trafficking of these receptors to and from the plasma membrane and their desensitization play a significant role in morphine tolerance (4,5). As with other GPCRs, these processes are modulated by phosphorylation at diverse sites within intracellular domains (6). Among other sites, agonist-specific phosphorylation of serine 375 in mouse (serine 377 in human) MOR is essential for its internalization (7).
|Human, Mouse, Rat|
Application Methods: Immunofluorescence (Frozen), Western Blotting
Background: N-methyl-D-aspartate receptor (NMDAR) forms a heterodimer of at least one NR1 and one NR2A-D subunit. Multiple receptor isoforms with distinct brain distributions and functional properties arise by selective splicing of the NR1 transcripts and differential expression of the NR2 subunits. NR1 subunits bind the co-agonist glycine and NR2 subunits bind the neurotransmitter glutamate. Activation of the NMDA receptor or opening of the ion channel allows flow of Na+ and Ca2+ ions into the cell, and K+ out of the cell (1). Each subunit has a cytoplasmic domain that can be directly modified by the protein kinase/phosphatase (2). PKC can phosphorylate the NR1 subunit (NMDAR1) of the receptor at Ser890/Ser896, and PKA can phosphorylate NR1 at Ser897 (3). The phosphorylation of NR1 by PKC decreases its affinity for calmodulin, thus preventing the inhibitory effect of calmodulin on NMDAR (4). The phosphorylation of NR1 by PKA probably counteracts the inhibitory effect of calcineurin on the receptor (5). NMDAR mediates long-term potentiation and slow postsynaptic excitation, which play central roles in learning, neurodevelopment, and neuroplasticity (6).