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PR01461

Identifier
KCNQ2CHANNEL  [View Relations]  [View Alignment]  
Accession
PR01461
No. of Motifs
4
Creation Date
01-DEC-2000
Title
KCNQ2 voltage-gated potassium channel signature
Database References
PRINTS; PR00169 KCHANNEL; PR01459 KCNQCHANNEL
Literature References
1. MILLER, C. 
An overview of the potassium channel family.
GENOME BIOL. 1(4) 1-5 (2000). 
 
2. ASHCROFT, F.M. 
Voltage-gated K+ channels.
IN ION CHANNELS AND DISEASE, ACADEMIC PRESS, 2000, PP.111-116.
 
3. SANGUINETTI, M. C.
Maximal function of minimal K+ channel subunits.
TRENDS PHARMACOL.SCI. 21 199-201 (2000).
 
4. WANG Q., CURRAN, M.E., SPLAWSKI, I., BURN, T.C., MILLHOLLAND, J.M.,
VANRAAY, T.J., SHEN, J., TIMOTHY, K.W., VINCENT, G.M., DE JAGER, T.,
SCHWARTZ, P.J., TOUBIN, J.A., MOSS, A.J., ATKINSON, D.L., LANDES, G.M.,
CONNORS, T.D. AND KEATING, M.T. 
Positional cloning of a novel potassium channel gene: KVLQT1 mutations cause
cardiac arrhythmias.
NAT.GENET. 12(1) 17-23 (1996).
 
5. BIERVERT, C., SCHROEDER, B.C., KUBISCH, C., BERKOVIC, S.F., PROPPING, P.,
JENTSCH, T.J. AND STEINLEIN O.K.
A potassium channel mutation in neonatal human epilepsy.
SCIENCE 279 403-406 (1998).
 
6. SCHROEDER, B.C., KUBISCH, C., STEIN, V. AND JENTSCH, T.J.
Moderate loss of function of cyclic-AMP-modulated KCNQ2/KCNQ3 K+ channels
causes epilepsy.
NATURE 396 687-690 (1998).

Documentation
Potassium ion (K+) channels are a structurally diverse group of proteins
that facilitate the flow of K+ ions across cell membranes. They are
ubiquitous, being present in virtually all cell types. Activation of K+
channels tends to hyperpolarise cells, reducing the membrane's electrical
resistance, dampening nervous activity. In eukaryotic cells, K+ channels
are involved in neural signalling and generation of the cardiac rhythm, and
act as effectors in signal transduction pathways involving G protein-
coupled receptors (GPCRs). In prokaryotic cells, they play a role in the
maintenance of ionic homeostasis [1].
 
Structurally, KCNQ channels belong to the subfamily of K+ channels whose
subunits contain 6 transmembrane (TM) domains: these are the voltage-gated
K+ channels, the KCNQ channels, the EAG-like K+ channels and 3 kinds of 
Ca2+-activated K+ channel (BK, IK and SK) [2]. All K+ channels share a
characteristic sequence feature: a TMxTVGYG motif that resides between
the 2 C-terminal membrane-spanning helices, and forms the K+-selective 
pore domain [1].
 
KCNQ channels differ from other voltage-gated 6 TM helix channels, chiefly 
in that they possess no tetramerisation domain. Consequently, they rely on
interaction with accessory subunits, or form heterotetramers with other
members of the family [3]. Currently, 5 members of the KCNQ family are 
known. These have been found to be widely distributed within the body,
having been shown to be expressed in the heart, brain, pancreas, lung,
placenta and ear. They were initially cloned as a result of a search for 
proteins involved in cardiac arhythmia. Subsequently, mutations in other 
KCNQ family members have been shown to be responsible for some forms of
hereditary deafness [4] and benign familial neonatal epilepsy [5].
 
The KCNQ2 channel subunit is thought to form active channels by hetero-
tetramerisation with KCNQ3, although some K+ channel activity does results
from the expression of KCNQ2 alone [6]. Channel function is modulated by
phosphorylation, since experiments have demonstrated that an increase in
intracellular cAMP concentration can enhance channel activity [2].
Frameshift mutations in both KCNQ2 and KCNQ3 are associated with benign
familial neonatal epilepsy [6], a disorder where an infant begins to suffer
convulsions, within the first three days of life. These symptoms usually
disappear after approximately three months, but affected individuals have a
higher than average chance of subsequently developing epilepsy (10-15%), in
later life [5].
 
KCNQ2CHANNEL is a 4-element fingerprint that provides a signature for the
KCNQ2 voltage-gated potassium channel. The fingerprint was derived from an
initial alignment of 16 sequences: the motifs were drawn from conserved
regions spanning the N-terminal third of the alignment, focusing on those
sections that characterise the KCNQ2 channel but distinguish it from other
members of the K+ channel superfamily - motifs 1 and 2 span the N-terminal
intracellular region; and motifs 3 and 4 span putative TM domains 1 and 2,
and the extracellular loop connecting them. Two iterations on SPTR39_14f 
were required to reach convergence, at which point a true set comprising 17
sequences was identified. A single partial match was also found, CIQ4_HUMAN,
the closely related human KCNQ4 channel, which matches motifs 3 and 4.
Summary Information
  17 codes involving  4 elements
0 codes involving 3 elements
1 codes involving 2 elements
Composite Feature Index
417171717
30000
20011
1234
True Positives
O43526        O43796        O75580        O88943        
O95845 Q99454 Q9QWN9 Q9Z342
Q9Z343 Q9Z344 Q9Z345 Q9Z346
Q9Z347 Q9Z348 Q9Z349 Q9Z350
Q9Z351
True Positive Partials
Codes involving 2 elements
CIQ4_HUMAN
Sequence Titles
O43526      POTASSIUM CHANNEL - Homo sapiens (Human).     
O43796 VOLTAGE GATED POTASSIUM CHANNEL - Homo sapiens (Human).
O75580 NEURONAL DELAYED-RECTIFIER VOLTAGE-GATED POTASSIUM CHANNEL SPLICE VARIANT - Homo sapiens (Human).
O88943 POTASSIUM CHANNEL - Rattus norvegicus (Rat).
O95845 POTASSIUM CHANNEL - Homo sapiens (Human).
Q99454 NEUROBLASTOMA-SPECIFIC POTASSIUM CHANNEL PROTEIN - Homo sapiens (Human).
Q9QWN9 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z342 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z343 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z344 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z345 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z346 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z347 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z348 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z349 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z350 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).
Q9Z351 ALTERNATIVE SPLICING:SEE ACCESSION BETWEEN AB000494 AND AB000504 - Mus musculus (Mouse).

CIQ4_HUMAN VOLTAGE-GATED POTASSIUM CHANNEL PROTEIN KQT-LIKE 4 - Homo sapiens (Human).
Scan History
SPTR39_14f 2  200  NSINGLE    
Initial Motifs
Motif 1  width=20
Element Seqn Id St Int Rpt
MVQKSRNGGVYPGTSGEKKL O88943 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z351 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z350 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z349 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z348 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z347 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z345 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z344 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z343 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z342 1 1 -
MVQKSRNGGVYPGPSGEKKL O43526 1 1 -
MVQKSRNGGVYPGPSGEKKL O43796 1 1 -
MVQKSRNGGVYPGPSGEKKL O75580 1 1 -
MVQKSRNGGVYPGPSGEKKL O95845 1 1 -
MVQKSRNGGVYPGPSGEKKL Q99454 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z346 1 1 -

Motif 2 width=17
Element Seqn Id St Int Rpt
KVGFVGLDPGAPDSTRD Q9Z344 21 0 -
KVGFVGLDPGAPDSTRD O88943 21 0 -
KVGFVGLDPGAPDSTRD Q9Z351 21 0 -
KVGFVGLDPGAPDSTRD Q9Z350 21 0 -
KVGFVGLDPGAPDSTRD Q9Z349 21 0 -
KVGFVGLDPGAPDSTRD Q9Z348 21 0 -
KVGFVGLDPGAPDSTRD Q9Z347 21 0 -
KVGFVGLDPGAPDSTRD Q9Z345 21 0 -
KVGFVGLDPGAPDSTRD Q9Z343 21 0 -
KVGFVGLDPGAPDSTRD Q9Z342 21 0 -
KVGFVGLDPGAPDSTRD O43526 21 0 -
KVGFVGLDPGAPDSTRD O43796 21 0 -
KVGFVGLDPGAPDSTRD O75580 21 0 -
KVGFVGLDPGAPDSTRD O95845 21 0 -
KVGFVGLDPGAPDSTRD Q99454 21 0 -
KVGFVGLDPGAPDSTRD Q9Z346 21 0 -

Motif 3 width=19
Element Seqn Id St Int Rpt
CLVLSVFSTIKEYEKSSEG Q9Z346 106 68 -
CLVLSVFSTIKEYEKSSEG O88943 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z351 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z350 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z349 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z348 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z347 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z345 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z344 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z343 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z342 106 68 -
CLVLSVFSTIKEYEKSSEG O43526 106 68 -
CLVLSVFSTIKEYEKSSEG O43796 106 68 -
CLVLSVFSTIKEYEKSSEG O75580 106 68 -
CLVLSVFSTIKEYEKSSEG O95845 106 68 -
CLVLSVFSTIKEYEKSSEG Q99454 106 68 -

Motif 4 width=12
Element Seqn Id St Int Rpt
ALYILEIVTIVV Q99454 125 0 -
ALYILEIVTIVV Q9Z351 125 0 -
ALYILEIVTIVV Q9Z350 125 0 -
ALYILEIVTIVV Q9Z349 125 0 -
ALYILEIVTIVV Q9Z348 125 0 -
ALYILEIVTIVV Q9Z347 125 0 -
ALYILEIVTIVV Q9Z345 125 0 -
ALYILEIVTIVV Q9Z344 125 0 -
ALYILEIVTIVV O88943 125 0 -
ALYILEIVTIVV Q9Z343 125 0 -
ALYILEIVTIVV Q9Z342 125 0 -
ALYILEIVTIVV O43526 125 0 -
ALYILEIVTIVV O43796 125 0 -
ALYILEIVTIVV O75580 125 0 -
ALYILEIVTIVV O95845 125 0 -
PLYILEIVTIVV Q9Z346 125 0 -
Final Motifs
Motif 1  width=20
Element Seqn Id St Int Rpt
MVQKSRNGGVYPGTSGEKKL O88943 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z351 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z350 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z349 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z348 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z347 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z345 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z344 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z343 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z342 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9QWN9 1 1 -
MVQKSRNGGVYPGPSGEKKL O43526 1 1 -
MVQKSRNGGVYPGPSGEKKL O43796 1 1 -
MVQKSRNGGVYPGPSGEKKL O75580 1 1 -
MVQKSRNGGVYPGPSGEKKL O95845 1 1 -
MVQKSRNGGVYPGPSGEKKL Q99454 1 1 -
MVQKSRNGGVYPGTSGEKKL Q9Z346 1 1 -

Motif 2 width=17
Element Seqn Id St Int Rpt
KVGFVGLDPGAPDSTRD Q9Z343 21 0 -
KVGFVGLDPGAPDSTRD O88943 21 0 -
KVGFVGLDPGAPDSTRD Q9Z351 21 0 -
KVGFVGLDPGAPDSTRD Q9Z350 21 0 -
KVGFVGLDPGAPDSTRD Q9Z349 21 0 -
KVGFVGLDPGAPDSTRD Q9Z348 21 0 -
KVGFVGLDPGAPDSTRD Q9Z347 21 0 -
KVGFVGLDPGAPDSTRD Q9Z345 21 0 -
KVGFVGLDPGAPDSTRD Q9Z344 21 0 -
KVGFVGLDPGAPDSTRD Q9Z342 21 0 -
KVGFVGLDPGAPDSTRD Q9QWN9 21 0 -
KVGFVGLDPGAPDSTRD O43526 21 0 -
KVGFVGLDPGAPDSTRD O43796 21 0 -
KVGFVGLDPGAPDSTRD O75580 21 0 -
KVGFVGLDPGAPDSTRD O95845 21 0 -
KVGFVGLDPGAPDSTRD Q99454 21 0 -
KVGFVGLDPGAPDSTRD Q9Z346 21 0 -

Motif 3 width=19
Element Seqn Id St Int Rpt
CLVLSVFSTIKEYEKSSEG Q9Z346 106 68 -
CLVLSVFSTIKEYEKSSEG O88943 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z351 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z350 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z349 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z348 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z347 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z345 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z344 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z343 106 68 -
CLVLSVFSTIKEYEKSSEG Q9Z342 106 68 -
CLVLSVFSTIKEYEKSSEG Q9QWN9 106 68 -
CLVLSVFSTIKEYEKSSEG O43526 106 68 -
CLVLSVFSTIKEYEKSSEG O43796 106 68 -
CLVLSVFSTIKEYEKSSEG O75580 106 68 -
CLVLSVFSTIKEYEKSSEG O95845 106 68 -
CLVLSVFSTIKEYEKSSEG Q99454 106 68 -

Motif 4 width=12
Element Seqn Id St Int Rpt
ALYILEIVTIVV Q99454 125 0 -
ALYILEIVTIVV Q9Z351 125 0 -
ALYILEIVTIVV Q9Z350 125 0 -
ALYILEIVTIVV Q9Z349 125 0 -
ALYILEIVTIVV Q9Z348 125 0 -
ALYILEIVTIVV Q9Z347 125 0 -
ALYILEIVTIVV Q9Z345 125 0 -
ALYILEIVTIVV Q9Z344 125 0 -
ALYILEIVTIVV Q9Z343 125 0 -
ALYILEIVTIVV O88943 125 0 -
ALYILEIVTIVV Q9Z342 125 0 -
ALYILEIVTIVV Q9QWN9 125 0 -
ALYILEIVTIVV O43526 125 0 -
ALYILEIVTIVV O43796 125 0 -
ALYILEIVTIVV O75580 125 0 -
ALYILEIVTIVV O95845 125 0 -
PLYILEIVTIVV Q9Z346 125 0 -