Potassium voltage-gated channel subfamily D member 2 (Voltage-gated potassium channel subunit Kv4.2)
1_MAAGV 6_ AAWLP 11_ FARAA 16_ AIGWM 21_ PVASG 26_ PMPAP 31_ PRQER 36_ KRTQD 41_ ALIVL 46_ NVSGT 51_ RFQTW 56_ QDTLE 61_ RYPDT 66_ LLGSS 71_ ERDFF 76_ YHPET 81_ QQYFF 86_ DRDPD 91_ IFRHI 96_ LNFYR 101_ TGKLH 106_ YPRHE 111_ CISAY 116_ DEELA 121_ FFGLI 126_ PEIIG 131_ DCCYE 136_ EYKDR 141_ RRENA 146_ ERLQD 151_ DADTD 156_ TAGES 161_ ALPTM 166_ TARQR 171_ VWRAF 176_ ENPHT 181_ STMAL 186_ VFYYV 191_ TGFFI 196_ AVSVI 201_ ANVVE 206_ TVPCG 211_ SSPGH 216_ IKELP 221_ CGERY 226_ AVAFF 231_ CLDTA 236_ CVMIF 241_ TVEYL 246_ LRLAA 251_ APSRY 256_ RFVRS 261_ VMSII 266_ DVVAI 271_ LPYYI 276_ GLVMT 281_ DNEDV 286_ SGAFV 291_ TLRVF 296_ RVFRI 301_ FKFSR 306_ HSQGL 311_ RILGY 316_ TLKSC 321_ ASELG 326_ FLLFS 331_ LTMAI 336_ IIFAT 341_ VMFYA 346_ EKGSS 351_ ASKFT 356_ SIPAA 361_ FWYTI 366_ VTMTT 371_ LGYGD 376_ MVPKT 381_ IAGKI 386_ FGSIC 391_ SLSGV 396_ LVIAL 401_ PVPVI 406_ VSNFS 411_ RIYHQ 416_ NQRAD 421_ KRRAQ 426_ KKARL 431_ ARIRA 436_ AKSGS 441_ ANAYM 446_ QSKRN 451_ GLLSN 456_ QLQSS 461_ EDEQA 466_ FVSKS 471_ GSSFE 476_ TQHHH 481_ LLHCL 486_ EKTTN 491_ HEFVD 496_ EQVFE 501_ ESCME 506_ VATVN 511_ RPSSH 516_ SPSLS 521_ SQQGV 526_ TSTCC 531_ SRRHK 536_ KTFRI 541_ PNANV 546_ SGSHQ 551_ GSIQE 556_ LSTIQ 561_ IRCVE 566_ RTPLS 571_ NSRSS 576_ LNAKM 581_ EECVK 586_ LNCEQ 591_ PYVTT 596_ AIISI 601_ PTPPV 606_ TTPEG 611_ DDRPE 616_ SPEYS 621_GGNIV
1: 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 rhythm 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 (PubMed:10551270, PubMed:11507158, PubMed:14623880, PubMed:14695263, PubMed:14980201, PubMed:15454437, PubMed:16934482, PubMed:19171772, PubMed:24501278, PubMed:24811166, PubMed:34552243, PubMed:35597238). The channel alternates between opened and closed conformations in response to the voltage difference across the membrane (PubMed:11507158). 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 (PubMed:14623880, PubMed:14980201, PubMed:15454437, PubMed:19171772, PubMed:24501278, PubMed:24811166). Likewise, interaction with DPP6 or DPP10 promotes expression at the cell membrane and regulates both channel characteristics and activity (By similarity). Upon depolarization, the channel goes from a resting closed state (C state) to an activated but non-conducting state (C* state), from there, the channel may either inactivate (I state) or open (O state) (PubMed:35597238)