Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Evidence for two concentration-dependent processes for beta-subunit effects on alpha1B calcium channels.
Cantí C, Davies A, Berrow NS, Butcher AJ, Page KM, Dolphin AC.
???displayArticle.abstract???
beta-Subunits of voltage-dependent Ca(2+) channels regulate both their expression and biophysical properties. We have injected a range of concentrations of beta3-cDNA into Xenopus oocytes, with a fixed concentration of alpha1B (Ca(V)2.2) cDNA, and have quantified the corresponding linear increase of beta3 protein. The concentration dependence of a number of beta3-dependent processes has been studied. First, the dependence of the a1B maximum conductance on beta3-protein occurs with a midpoint around the endogenous concentration of beta3 (approximately 17 nM). This may represent the interaction of the beta-subunit, responsible for trafficking, with the I-II linker of the nascent channel. Second, the effect of beta3-subunits on the voltage dependence of steady-state inactivation provides evidence for two channel populations, interpreted as representing alpha1B without or with a beta3-subunit, bound with a lower affinity of 120 nM. Third, the effect of beta3 on the facilitation rate of G-protein-modulated alpha1B currents during a depolarizing prepulse to +100 mV provides evidence for the same two populations, with the rapid facilitation rate being attributed to Gbetagamma dissociation from the beta-subunit-bound alpha1B channels. The data are discussed in terms of two hypotheses, either binding of two beta-subunits to the alpha1B channel or a state-dependent alteration in affinity of the channel for the beta-subunit.
Baylor,
Calcium release and sarcoplasmic reticulum membrane potential in frog skeletal muscle fibres.
1984, Pubmed
Baylor,
Calcium release and sarcoplasmic reticulum membrane potential in frog skeletal muscle fibres.
1984,
Pubmed Bell,
Biophysical properties, pharmacology, and modulation of human, neuronal L-type (alpha(1D), Ca(V)1.3) voltage-dependent calcium currents.
2001,
Pubmed Berrou,
Molecular determinants of inactivation within the I-II linker of alpha1E (CaV2.3) calcium channels.
2001,
Pubmed
,
Xenbase Bichet,
The I-II loop of the Ca2+ channel alpha1 subunit contains an endoplasmic reticulum retention signal antagonized by the beta subunit.
2000,
Pubmed
,
Xenbase Birnbaumer,
Structures and functions of calcium channel beta subunits.
1998,
Pubmed
,
Xenbase Bogdanov,
Acidic motif responsible for plasma membrane association of the voltage-dependent calcium channel beta1b subunit.
2000,
Pubmed
,
Xenbase Bourinet,
Determinants of the G protein-dependent opioid modulation of neuronal calcium channels.
1996,
Pubmed
,
Xenbase Brabet,
Multiple species and isoforms of Bordetella pertussis toxin substrates.
1988,
Pubmed Brice,
Importance of the different beta subunits in the membrane expression of the alpha1A and alpha2 calcium channel subunits: studies using a depolarization-sensitive alpha1A antibody.
1997,
Pubmed Burgess,
beta subunit reshuffling modifies N- and P/Q-type Ca2+ channel subunit compositions in lethargic mouse brain.
1999,
Pubmed Campbell,
Voltage-dependent calcium channel beta-subunits in combination with alpha 1 subunits, have a GTPase activating effect to promote the hydrolysis of GTP by G alpha o in rat frontal cortex.
1995,
Pubmed Campbell,
Inhibition of the interaction of G protein G(o) with calcium channels by the calcium channel beta-subunit in rat neurones.
1995,
Pubmed Cantí,
Identification of residues in the N terminus of alpha1B critical for inhibition of the voltage-dependent calcium channel by Gbeta gamma.
1999,
Pubmed
,
Xenbase Cantí,
Interaction between G proteins and accessory subunits in the regulation of 1B calcium channels in Xenopus oocytes.
2000,
Pubmed
,
Xenbase Day,
The expression of voltage-dependent calcium channel beta subunits in human hippocampus.
1998,
Pubmed De Waard,
Direct binding of G-protein betagamma complex to voltage-dependent calcium channels.
1997,
Pubmed
,
Xenbase De Waard,
Subunit regulation of the neuronal alpha 1A Ca2+ channel expressed in Xenopus oocytes.
1995,
Pubmed
,
Xenbase De Waard,
Properties of the alpha 1-beta anchoring site in voltage-dependent Ca2+ channels.
1995,
Pubmed
,
Xenbase Dolphin,
Mechanisms of modulation of voltage-dependent calcium channels by G proteins.
1998,
Pubmed Hanlon,
Modelling of a voltage-dependent Ca2+ channel beta subunit as a basis for understanding its functional properties.
1999,
Pubmed Herlitze,
Molecular determinants of inactivation and G protein modulation in the intracellular loop connecting domains I and II of the calcium channel alpha1A subunit.
1997,
Pubmed Hosey,
L-type calcium channels in cardiac and skeletal muscle. Purification and phosphorylation.
1989,
Pubmed Meir,
Calcium channel beta subunit promotes voltage-dependent modulation of alpha 1 B by G beta gamma.
2000,
Pubmed Pragnell,
Calcium channel beta-subunit binds to a conserved motif in the I-II cytoplasmic linker of the alpha 1-subunit.
1994,
Pubmed Qin,
Direct interaction of gbetagamma with a C-terminal gbetagamma-binding domain of the Ca2+ channel alpha1 subunit is responsible for channel inhibition by G protein-coupled receptors.
1997,
Pubmed
,
Xenbase Roche,
Ca2+ channel beta3 subunit enhances voltage-dependent relief of G-protein inhibition induced by muscarinic receptor activation and Gbetagamma.
1998,
Pubmed
,
Xenbase Stephens,
The alpha1B Ca2+ channel amino terminus contributes determinants for beta subunit-mediated voltage-dependent inactivation properties.
2000,
Pubmed Stephens,
Facilitation of rabbit alpha1B calcium channels: involvement of endogenous Gbetagamma subunits.
1998,
Pubmed Stephens,
Functional expression of rat brain cloned alpha1E calcium channels in COS-7 cells.
1997,
Pubmed Tanabe,
Primary structure of the receptor for calcium channel blockers from skeletal muscle.
,
Pubmed Tareilus,
A Xenopus oocyte beta subunit: evidence for a role in the assembly/expression of voltage-gated calcium channels that is separate from its role as a regulatory subunit.
1997,
Pubmed
,
Xenbase Walker,
A beta 4 isoform-specific interaction site in the carboxyl-terminal region of the voltage-dependent Ca2+ channel alpha 1A subunit.
1998,
Pubmed Walker,
A new beta subtype-specific interaction in alpha1A subunit controls P/Q-type Ca2+ channel activation.
1999,
Pubmed
,
Xenbase Witcher,
Subunit identification and reconstitution of the N-type Ca2+ channel complex purified from brain.
1993,
Pubmed Wu,
Intramolecular interactions regulate SAP97 binding to GKAP.
2000,
Pubmed Yamaguchi,
Multiple modulation pathways of calcium channel activity by a beta subunit. Direct evidence of beta subunit participation in membrane trafficking of the alpha1C subunit.
1998,
Pubmed
,
Xenbase Zamponi,
Crosstalk between G proteins and protein kinase C mediated by the calcium channel alpha1 subunit.
1997,
Pubmed
,
Xenbase Zamponi,
Decay of prepulse facilitation of N type calcium channels during G protein inhibition is consistent with binding of a single Gbeta subunit.
1998,
Pubmed
