KCND2 - Potassium voltage-gated channel subfamily D member 2 - human protein (Function)
 
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KCND2 »  Potassium voltage-gated channel subfamily D member 2
 
Protein also known as:  Voltage-gated potassium channel subunit Kv4.2.
Gene name:  KCND2
Entry whose protein(s) existence is based on evidence at protein level
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1 72 1
GENE REF ISO

Function

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Overview 
Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes, primarily in the brain. Mediates the major part of the dendritic A-type current I(SA) in brain neurons (By similarity). This current is activated at membrane potentials that are below the threshold for action potentials. It regulates neuronal excitability, prolongs the latency before the first spike in a series of action potentials, regulates the frequency of repetitive action potential firing, shortens the duration of action potentials and regulates the back-propagation of action potentials from the neuronal cell body to the dendrites. Contributes to the regulation of the circadian rhytm of action potential firing in suprachiasmatic nucleus neurons, which regulates the circadian rhythm of locomotor activity (By similarity). Functions downstream of the metabotropic glutamate receptor GRM5 and plays a role in neuronal excitability and in nociception mediated by activation of GRM5 (By similarity). Mediates the transient outward current I(to) in rodent heart left ventricle apex cells, but not in human heart, where this current is mediated by another family member. Forms tetrameric potassium-selective channels through which potassium ions pass in accordance with their electrochemical gradient (PubMed10551270, PubMed15454437, PubMed14695263, PubMed14623880, PubMed14980201, PubMed16934482, PubMed24811166, PubMed24501278). The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed11507158). Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCND2 and KCND3; channel properties depend on the type of pore-forming alpha subunits that are part of the channel. In vivo, membranes probably contain a mixture of heteromeric potassium channel complexes. Interaction with specific isoforms of the regulatory subunits KCNIP1, KCNIP2, KCNIP3 or KCNIP4 strongly increases expression at the cell surface and thereby increases channel activity; it modulates the kinetics of channel activation and inactivation, shifts the threshold for channel activation to more negative voltage values, shifts the threshold for inactivation to less negative voltages and accelerates recovery after inactivation (PubMed15454437, PubMed14623880, PubMed14980201, PubMed19171772, PubMed24501278, PubMed24811166). Likewise, interaction with DPP6 or DPP10 promotes expression at the cell membrane and regulates both channel characteristics and activity (By similarity).  
14
  • UniProtKB
According to TCDB this is a transporter from family:
the voltage-gated ion channel (vic) superfamily  1.A.1.2.5  
GO molecular function 
A-type (transient outward) potassium channel activitydefinition[GO:0005250]  
3
  • UniProtKB
  • Ortholog Curator
  • RefGenome
Not  Delayed rectifier potassium channel activitydefinition[GO:0005251]  
1
  • RefGenome
Metal ion bindingdefinition[GO:0046872]  
1
  • UniProtKB KW
Protein bindingdefinition[GO:0005515]  
4
  • IntAct
  • UniProtKB
Voltage-gated potassium channel activitydefinition[GO:0005249]  
3
  • UniProtKB
  • Ortholog Curator
GO biological process 
Action potentialdefinition[GO:0001508]  
1
  • UniProtKB
Cellular response to hypoxiadefinition[GO:0071456]  
1
  • Ortholog Curator
Potassium ion transmembrane transportdefinition[GO:0071805]  
3
  • UniProtKB
  • RefGenome
Protein homooligomerizationdefinition[GO:0051260] silver  
1
  • InterPro 2 GO
Regulation of ion transmembrane transportdefinition[GO:0034765]  
1
  • UniProtKB KW
Synaptic transmissiondefinition[GO:0007268]  
1
  • UniProtKB
Pathways 
According to Reactome, this protein belongs to the following pathway:
Voltage gated Potassium channels  REACT_75770  
Note 
The transient neuronal A-type potassium current called I(SA) is triggered at membrane potentials that are below the threshold for action potentials. It inactivates rapidly and recovers rapidly from inactivation. It regulates the firing of action potentials and plays a role in synaptic integration and plasticity. Potassium channels containing KCND2 account for about 80% of the neuronal A-type potassium current. In contrast, the potassium channel responsible for the cardiac I(to) current differs between species; it is mediated by KCND2 in rodents. In human and other non-rodents KCND3 may play an equivalent role.  
4
  • UniProtKB
 

Keywords

Biological process 
Ion transport  definition   [KW-0406]
Potassium transport  definition   [KW-0633]
Transport  definition   [KW-0813]
Molecular function 
Ion channel  definition   [KW-0407]
Potassium channel  definition   [KW-0631]
Voltage-gated channel  definition   [KW-0851]
Technical term 
Reference proteome  definition   [KW-1185]
 

Further external links

GeneWiki: KCND2
GenomeRNAi: 3751
PRO: PR:Q9NZV8