Background: | 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. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane. 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 α 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. Likewise, interaction with DPP6 or DPP10 promotes expression at the cell membrane and regulates both channel characteristics and activity (By similarity). |
Synonyms: | Potassium voltage-gated channel subfamily D member 2 (Voltage-gated potassium channel subunit Kv4.2), KCND2, KIAA1044 |
UniProt Protein Function: | Kv4.2: Pore-forming (alpha) subunit of voltage-gated rapidly inactivating A-type potassium channels. May contribute to I(To) current in heart and I(Sa) current in neurons. Channel properties are modulated by interactions with other alpha subunits and with regulatory subunits. Belongs to the potassium channel family. D (Shal) (TC 1.A.1.2) subfamily. Kv4.2/KCND2 sub-subfamily. |
UniProt Protein Details: | Protein type:Membrane protein, integral; Membrane protein, multi-pass; Channel, potassium Chromosomal Location of Human Ortholog: 7q31 Cellular Component: postsynaptic membrane; voltage-gated potassium channel complex; integral to plasma membrane; integral to membrane; plasma membrane; dendritic spine; intrinsic to plasma membrane Molecular Function:protein binding; voltage-gated potassium channel activity; delayed rectifier potassium channel activity; metal ion binding; A-type (transient outward) potassium channel activity Biological Process: regulation of action potential; synaptic transmission; protein homooligomerization |
NCBI Summary: | Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shal-related subfamily, members of which form voltage-activated A-type potassium ion channels and are prominent in the repolarization phase of the action potential. This member mediates a rapidly inactivating, A-type outward potassium current which is not under the control of the N terminus as it is in Shaker channels. [provided by RefSeq, Jul 2008] |
UniProt Code: | Q9NZV8 |
NCBI GenInfo Identifier: | 38258257 |
NCBI Gene ID: | 3751 |
NCBI Accession: | Q9NZV8.2 |
UniProt Secondary Accession: | Q9NZV8,O95012, O95021, Q2TBD3, Q9UBY7, Q9UN98, Q9UNH9 |
UniProt Related Accession: | Q9NZV8 |
Molecular Weight: | 630 |
NCBI Full Name: | Potassium voltage-gated channel subfamily D member 2 |
NCBI Synonym Full Names: | potassium voltage-gated channel, Shal-related subfamily, member 2 |
NCBI Official Symbol: | KCND2 |
NCBI Official Synonym Symbols: | RK5; KV4.2 |
NCBI Protein Information: | potassium voltage-gated channel subfamily D member 2; voltage-sensitive potassium channel; voltage-gated potassium channel subunit Kv4.2 |
UniProt Protein Name: | Potassium voltage-gated channel subfamily D member 2 |
UniProt Synonym Protein Names: | Voltage-gated potassium channel subunit Kv4.2 |
Protein Family: | Potassium voltage-gated channel subfamily |
UniProt Gene Name: | KCND2 |
UniProt Entry Name: | KCND2_HUMAN |