Proteopedia - User contributions [en]

User talk:Kyle Barrett/Voltage-gated calcium channels

2009-12-18T13:51:07Z

Kyle Barrett: User talk:Kyle Barrett/Voltage-gated calcium channels moved to Talk:Voltage-gated calcium channels

#REDIRECT [[Talk:Voltage-gated calcium channels]]

Voltage-gated calcium channels

2009-12-18T13:51:06Z

Kyle Barrett: User:Kyle Barrett/Voltage-gated calcium channels moved to Voltage-gated calcium channels

{{STRUCTURE_1t0j | PDB=1t0j | SCENE=User:Kyle_Barrett/Secondary_structure/1}}

== Introduction ==

Voltage-gated calcium channels play crucial roles in many bodily functions including: cardiac action potentials, neurotransmitter release, muscle contraction. During neurological functions, these calcium channels create action potentials<ref name="Van Petegem F, Minor DL Jr">PMID:17052221</ref>. At resting state,voltage-gated calcium channels are in a closed conformation. When the membrane is depolarized, they are open. These channels initiate the release of neurotransmitters at synapses, and have a powerful influence on synaptic strength. The nervous system requires different levels of calcium concentration, so when transmitter release occurs, high levels of calcium are needed. During short-term facilitation, slow steady streams of calcium build up. Failure of these calcium channels can result in migranes, ataxia, and also other neurological diseases. Calmodulin is a specific calcium channel sensor, and regulates the functions of the channel. Calcium binding to calmodulin regulates the facilitation of Ca2+ through the coltage-gated channels.<ref name="Halling, Parks, Hamilton">PMID:16369047</ref>

== Function ==
These calcium channels regulate the entry of calcium ions into excitable cells. The isoform alpha-1C gives rise to L-type calcium currents. Long-lasting (L-type) calcium channels belong to the 'high-voltage activated' (HVA) group. They are blocked by dihydropyridines (DHP), phenylalkylamines, benzothiazepines, and by omega-agatoxin-IIIA (omega-Aga-IIIA). They are however insensitive to omega-conotoxin-GVIA (omega-CTx-GVIA) and omega-agatoxin-IVA (omega-Aga-IVA).<ref name="Q13936">http://www.uniprot.org/uniprot/Q13936</ref> Calcium channels containing the alpha-1C subunit play an important role in excitation-contraction coupling in the heart. The various isoforms display marked differences in the sensitivity to DHP compounds. Binding of calmodulin or CABP1 at the same regulatory sites results in an opposit effects on the channel function. Some L-type calcium blockers include: dihydropyridines, phenylalkylamines, and benzothiazepines.

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== Structure ==
This specific protein is a two chain structure and was first found in Rattus norvegicus.

The beta-interaction domain (BID), formed the AID-binding site; however, this region is buried in the Ca(V)beta core and is unavailable for protein-protein interactions. The pore-forming α1-subunit of voltage-gated Ca2+ channels (Cav)2 is composed of four homologous domains (I-IV), each of which has six transmembrane segments (S1–S6).

<applet load='1t0j' size='320' frame='true' align='left' caption='VOLTAGE-GATED CALCIUM CHANNNEL' />

When viewed in <scene name='User:Kyle_Barrett/N_to_c_rainbow_by_monomer/1'>N->C Color Coding</scene> (where the '''N-terminus''' is gradually shaded into the '''C-terminus''' according to the scale below)
{{Template:ColorKey_N2CRainbow}}

== Channel Signaling ==
The amount of Ca(2+) entering through these channels is modulated by a plethora of intracellular messenger molecules, including betagamma-subunits of G proteins, and protein kinases.<ref name="Zamponi, Jarvis">PMID:11583809</ref> Recent studies show that second messengers and presynaptic vesicle-release proteins don't directly effect calcium activity, but there is definately cross talk between the second messengers and the channel.

== Pore and Gating Structure ==
Voltage-dependent calcium channels are formed as a complex of several different subunits: α1, α2δ, β1-4, and γ. The α1 subunit forms the ion conducting pore while the associated subunits have several functions including modulation of gating.<ref name="Dolphin AC">PMID:16402121</ref>

<ref name="Van Petegem F, Minor DL Jr">PMID:17052221</ref>

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[http://www.ncbi.nlm.nih.gov/pubmed/17052221]
[[http://www.ncbi.nlm.nih.gov/pubmed/18817729?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_TitleSearch&linkpos=1&log$=pmtitlesearch4]]
[[http://www.ncbi.nlm.nih.gov/pubmed/18817727?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedreviews&logdbfrom=pubmed]]
[[http://www.jbc.org/content/282/6/3864.full]]
[[Catterall, W. A., Perez-Reyes, E., Snutch, T. P., and Striessnig, J. (2005) Pharmacol. Rev. 57, 411-425Abstract/FREE Full Text]]
[http://www.ncbi.nlm.nih.gov/pubmed/16369047?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedreviews&logdbfrom=pubmed]

User talk:Kyle Barrett

2009-12-18T13:49:49Z

Kyle Barrett: User talk:Kyle Barrett moved to User talk:Kyle Barrett/Voltage-gated calcium channels

#REDIRECT [[User talk:Kyle Barrett/Voltage-gated calcium channels]]

User:Kyle Barrett

2009-12-18T13:49:49Z

Kyle Barrett: User:Kyle Barrett moved to User:Kyle Barrett/Voltage-gated calcium channels

#REDIRECT [[User:Kyle Barrett/Voltage-gated calcium channels]]

Voltage-gated calcium channels

2009-12-18T13:49:49Z

Kyle Barrett: User:Kyle Barrett moved to User:Kyle Barrett/Voltage-gated calcium channels

2009-10-05T01:12:23Z

Kyle Barrett:

Voltage-gated calcium channels

2009-10-04T17:24:24Z

Kyle Barrett:

2009-09-23T02:07:47Z

Kyle Barrett:

== Mitochondrial Carrier Proteins ==
<applet load='1okc' size='300' frame='true' align='right' caption='Insert caption here' />