Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Excitable cells often display rapid coordination of hormone-induced intracellular calcium signals. Calcium elevations that begin in a single epithelial cell also may spread to adjacent cells, but coordination of hormone-induced signals among epithelial cells has not been described. We report the use of confocal microscopy to determine the inter- and intracellular distribution of cytosolic calcium in isolated rat hepatocyte couplets, an isolated epithelial cell system in which functional polarity is maintained. Both vasopressin and phenylephrine evoked sequential coordinated calcium signals in the couplets, even during cytosolic calcium oscillations. The coupling was abolished by closure of intercellular gap junction channels by treatment with octanol. These observations demonstrate that hormone-induced intracellular calcium signals are coordinated among hepatocytes and suggest that gap junction channels mediate this intercellular integration of tissue responsiveness.
Mol Biol Cell 1992 Jan
PMID:Coordination of hormone-induced calcium signals in isolated rat hepatocyte couplets: demonstration with confocal microscopy. 155 Sep 53

Some theoretical aspects on structure and function of proteins have been discussed previously. Proteins form multimeric complexes, as they have the capability of binding other proteins (Lego property) resulting in multimeric complexes capable of emergent functions. Multimeric proteins might have either a genomic or a postgenomic origin. Proteins spanning the plasma membrane have been analyzed by considering the effects of the microenvironment in which the protein is embedded. In particular, the different effects of the hydrophilic (extracellular and intracellular) versus the lipophilic (intramembrane) environment have been considered. These aspects have been discussed in the framework of membrane microdomains, in particular, the so-called rafts. In alpha-helix proteins the individual peptide dipoles align to produce a macrodipole crossing the entire membrane. This macrodipole has its positive (extracellular) pole at the N-terminal end of the helix and its negative (intracellular) pole at the C-terminal end. This arrangement has been analyzed in the framework of the counter-ion atmosphere, that is, the formation of a cloud of small ions bearing an opposite charge. Excitable cells reverse their resting potential during the all-or-none action potentials. Hence, the extracellular side of the plasma membrane becomes negative with respect to the intracellular side. This change of polarization affects also the direction and magnitude of the alpha-helix dipole in view of the fact that there is a displacement of the counter ions. The oscillation in the intensity of the dipole caused by the action potentials opens the possibility of an interaction among dipoles by electromagnetic waves.
J Mol Neurosci 2005
PMID:How proteins come together in the plasma membrane and function in macromolecular assemblies: focus on receptor mosaics. 1601 87

Voltage-gated ion channels are well known for their functional roles in excitable tissues. Excitable tissues rely on voltage-gated ion channels and their auxiliary subunits to achieve concerted electrical activity in living cells. Auxiliary subunits are also known to provide functional diversity towards the transport and biogenesis properties of the principal subunits. Recent interests in pharmacological properties of these auxiliary subunits have prompted significant amounts of efforts in understanding their physiological roles. Some auxiliary subunits can potentially serve as drug targets for novel analgesics. Three families of sodium channel auxiliary subunits are described here: beta1 and beta3, beta2 and beta4, and temperature-induced paralytic E (TipE). While sodium channel beta-subunits are encoded in many animal genomes, TipE has only been found exclusively in insects. In this review, we present phylogenetic analyses, discuss potential evolutionary origins and functional data available for each of these subunits. For each family, we also correlate the functional specificity with the history of evolution for the individual auxiliary subunits.
J Mol Microbiol Biotechnol 2007
PMID:Sodium channel auxiliary subunits. 1758 73

Excitable cells have the capacity to modify their electrical properties in response to different stimuli. This specific feature is due to a flux of ion currents that flow via ion channels in the plasma membrane. In all species so far studied, ion channels are proteins expressed in the zygote and in the blastomeres of the developing embryo, and their activity is subject to dynamic changes throughout the early cleavage stages. Although these complex patterns imply that ion currents play a role in signal transduction and the control of embryogenesis, a specific developmental function for the appearance, loss, and alterations of the channels remains to be elucidated. This review reports several aspects surrounding the involvement of ion currents in early embryo development, from invertebrates to human. It focuses on the occurrence, modulation, and dynamic role of ion fluxes through external, intra- and inter-cellular ion channels from the zygote up to the blastula and pre-implantation stages. The implications for a role of ion currents in development, and their possible clinical and technological applications are discussed.
Mol Reprod Dev 2010 Oct
PMID:Dynamic roles of ion currents in early development. 2058 98

Excitable tissues rely on junctional membrane complexes to couple cell surface signals to intracellular channels. The junctophilins have emerged as a family of proteins critical in coordinating the maturation and maintenance of this cellular ultrastructure. Within skeletal and cardiac muscle, junctophilin 1 and junctophilin 2, respectively, couple sarcolemmal and intracellular calcium channels. In neuronal tissue, junctophilin 3 and junctophilin 4 may have an emerging role in coupling membrane neurotransmitter receptors and intracellular calcium channels. These important physiological roles are highlighted by the pathophysiology which results when these proteins are perturbed, and a growing body of literature has associated junctophilins with the pathogenesis of human disease.
Trends Mol Med 2014 Jun
PMID:The junctophilin family of proteins: from bench to bedside. 2463 42

Dendritic spines are the postsynaptic terminals of most excitatory synapses in the mammalian brain. Learning and memory are associated with long-lasting structural remodeling of dendritic spines through an actin-mediated process regulated by the Rho-family GTPases RhoA, Rac, and Cdc42. These GTPases undergo sustained activation after synaptic stimulation, but whereas Rho activity can spread from the stimulated spine, Cdc42 activity remains localized to the stimulated spine. Because Cdc42 itself diffuses rapidly in and out of the spine, the basis for the retention of Cdc42 activity in the stimulated spine long after synaptic stimulation has ceased is unclear. Here we model the spread of Cdc42 activation at dendritic spines by means of reaction-diffusion equations solved on spine-like geometries. Excitable behavior arising from positive feedback in Cdc42 activation leads to spreading waves of Cdc42 activity. However, because of the very narrow neck of the dendritic spine, wave propagation is halted through a phenomenon we term geometrical wave-pinning. We show that this can account for the localization of Cdc42 activity in the stimulated spine, and, of interest, retention is enhanced by high diffusivity of Cdc42. Our findings are broadly applicable to other instances of signaling in extreme geometries, including filopodia and primary cilia.
Mol Biol Cell 2015 Nov 05
PMID:Dendritic spine geometry can localize GTPase signaling in neurons. 2633 87