Penetrating at least one phospholipid bilayer of a membrane. May also refer to the state of being buried in the bilayer with no exposure outside the bilayer. When used to describe a protein, indicates that all or part of the peptide sequence is embedded in the membrane.
Double layer of lipid molecules that encloses all cells, and, in eukaryotes, many organelles; may be a single or double lipid bilayer; also includes associated proteins.
Recombinantly expressed NCAM180
specifically reduces inward currents of neuron-specific Kir3.1/
3.2 and Kir3.1/3.3 but not Kir3.1/3.4 channels in Xenopus
oocytes and CHO cells (Delling ).
NCAM, TrkB and Kir3.3 interact directly
with each other via their intracellular domains. Overexpression
of the developmentally late appearing Kir3.3 subunit leads to a
decrease in NCAM-mediated neurite outgrowth. Kir3.3 chan-
nel expression at the cell surface; thus activity is regulated by
NCAM and TrkB independently of BDNF ligand binding.
These observations indicate that the interplay of recognition
molecules, neurotrophin receptors, and ion channels regulate
neurite outgrowth. Kleene 
Kir3 channels are activated following stimulation of G
protein-coupled receptors (GPCRs) that use the Gi/o
family of G proteins. Stimulation of the GPCR promotes
exchange of GDP for GTP on the Gα subunit which, in
turn, leads to activation of the Gα subunit and the Gβγ
dimer. Gβγ dimers bind to and activate Kir3 channels
(Reuveny et al. 1994 ; Wickman et al. 1994 ; Huang et al.
1995 ). Gα subunits are required for terminating Kir3
activation. The intrinsic GTPase activity of the Gα subunit
hydrolyses GTP, leading to inactivation of the Gβγ dimer.
Regulator of G protein signalling (RGS) proteins accelerate
the GTPase activity of Gα subunits (GAP), leading to faster
activation and deactivation of Kir3 channels (Doupnik
et al. 1997 ). (From Fowler )
Kir3.3 subunit protein is expressed in raphe-derived axons at the light and electron microscopic
level, but none of the other Kir3 subfamily members or the KATP channel subunits Kir6.1 and Kir6.2. (Pruess )
5-HT autoreceptors and
G protein-gated inwardly rectifying potassium channels (Kir3/GIRK
family), as well as their functional connectivity, has been demonstrated in raphe neurons (Penington ).
The GluR7 receptor gene GRIK3 is located on
chromosome 1p34–33, where a significant linkage with schizo-
phrenia has been reported (DeLisi et al., 2002 . Significant changes
of GluR7 expression in schizophrenia have been reported in
multiple brain regions (Sokolov, 1998 ). (From )
The serotonergic system of the brainstem raphe is involved in mood control, the sleep-wake cycle, auto-
nomic function, and stress response. The axons of certain dorsal raphe neurons form a dense serotonergic
supraependymal plexus lining the brain ventricles, likely regulating ependymal metabolism and activity
including ciliary movements and glucose homeostasis. In raphe neurons, serotonin exerts its function
partly via 5-HT autoreceptors and G protein-gated inwardly rectifying potassium channels (Kir3/GIRK).
Kir3.3 containing potassium channels may be of functional importance in autoregulation and excitability
of supraependymal fibres and the complex serotonergic regulation along the parenchyma/CSF border. (Pruess )
Single channel Conductance of Kir3.3/Kir3.1 in CHO
Kir3.1/3.3 basal activity at different voltages applied to the patch membrane. No channel activity was observed at +60 mV