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PR01493

Identifier
KV8CHANNEL  [View Relations]  [View Alignment]  
Accession
PR01493
No. of Motifs
9
Creation Date
14-MAR-2001
Title
Kv8 potassium channel alpha subunit signature
Database References
PRINTS; PR00169 KCHANNEL; PR01491 KVCHANNEL
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.97-123.
 
3. SANSOM, M.S.
Putting the parts together.
CURR.BIOL. 9(19) R738-R741 (1999).   
 
4. SALINAS, M., DUPRAT, F., HEURTEAUX, C., HUGNOT, J-P. AND LAZDUNSKI, M.
New modulatory alpha subunits for mammalian shab K+ channels.
J.BIOL.CHEM. 272(39) 24371-24379 (1997).
 
5. SALINAS, M., DE WEILLE, J., GUILLEMARE, E., LAZDUNSKI, M. AND HUGNOT, J-P.
Modes of regulation of shab K+ channel activity by the Kv8.1 subunit.
J.BIOL.CHEM. 272(13) 8774-8780 (1997).

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, Kv channels belong to the subfamily of K+ channels whose
subunits contain 6 transmembrane (TM) domains: these are the voltage-
gated K+ (Kv) channels, the KCNQ channels, the EAG-like K+ channels and
3 kinds of Ca2+-activated K+ channels (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 [1-2].
 
The Kv family can be divided into 4 subfamilies on the basis of sequence
similarity and function: Shaker (Kv1), Shab (Kv2), Shaw (Kv3) and Shal 
(Kv4). All consist of pore-forming alpha subunits that associate with 
different types of beta subunit. To form a functional K+ channel pore,
4 alpha subunits and 4 beta subunits are required. The alpha subunits
have 6 well-conserved TM domains, a pore loop region and variable length
N- and C-termini. TM domains 5/6 and the loop region form the K+ 
channel pore through which the K+ ions pass [3]. 
 
More recently, 4 new electrically-silent alpha subunits have been cloned:
Kv5 (KCNF), Kv6 (KCNG), Kv8 and Kv9 (KCNS). These subunits do not themselves
possess any functional activity, but appear to form heteromeric channels
with Kv2 subunits, and thus modulate Shab channel activity [4]. When highly
expressed, they inhibit channel activity, but at lower levels show more
specific modulatory actions. Coexpression of Kv8 subunits with Shab subunits
produces altered channel-activation kinetics that do not fit the standard
model. In addition, channel inactivation shows a shift in voltage-dependence
toward more negative potentials and a slower time course. TM domain 6 is
thought to play a key role in these modulatory effects [5].
 
KV8CHANNEL is a 9-element fingerprint that provides a signature for the Kv8
potassium channel alpha subunits. The fingerprint was derived from an
initial alignment of 2 sequences: the motifs were drawn from conserved 
regions spanning virtually the full alignment length - motifs 1-7 reside in
the N-terminal cytoplasmic domain; motif 8 spans the C-terminus of TM domain
6, leading into the cytoplasmic C-terminus; and motif 9 resides in the 
C-terminal domain. Two iterations on SPTR39_15f were required to reach
convergence, at which point a true set comprising 3 sequences was identified.
Summary Information
3 codes involving  9 elements
0 codes involving 8 elements
0 codes involving 7 elements
0 codes involving 6 elements
0 codes involving 5 elements
0 codes involving 4 elements
0 codes involving 3 elements
0 codes involving 2 elements
Composite Feature Index
9333333333
8000000000
7000000000
6000000000
5000000000
4000000000
3000000000
2000000000
123456789
True Positives
P97557        Q60565        Q9UHJ4        
Sequence Titles
P97557      NEURONAL POTASSIUM CHANNEL - Rattus norvegicus (Rat). 
Q60565 POTASSIUM CHANNEL KV8.1 - Mesocricetus auratus (Golden hamster).
Q9UHJ4 NEURONAL POTASSIUM CHANNEL ALPHA SUBUNIT (POTASSIUM CHANNEL KV8.1) - Homo sapiens (Human).
Scan History
SPTR39_15f 2  5    NSINGLE    
Initial Motifs
Motif 1  width=15
Element Seqn Id St Int Rpt
FCSEGEGEPLALGDC Q9UHJ4 26 26 -
FCSEGEGEPLALGDC Q60565 30 30 -

Motif 2 width=16
Element Seqn Id St Int Rpt
GGSRFVLSQQALSCFP Q9UHJ4 46 5 -
GGSRFVLSQQALSCFP Q60565 50 5 -

Motif 3 width=15
Element Seqn Id St Int Rpt
PSPLELCDDANPVDN Q9UHJ4 85 23 -
PSPLELCDDANPVDN Q60565 89 23 -

Motif 4 width=14
Element Seqn Id St Int Rpt
GRLHVMEQLCALSF Q9UHJ4 120 20 -
GRLHVMEQLCALSF Q60565 124 20 -

Motif 5 width=19
Element Seqn Id St Int Rpt
QEIQYWGIDELSIDSCCRD Q9UHJ4 135 1 -
QEIQYWGIDELSIDSCCRD Q60565 139 1 -

Motif 6 width=14
Element Seqn Id St Int Rpt
RYFRRKELSETLDF Q9UHJ4 154 0 -
RYFRRKELSETLDF Q60565 158 0 -

Motif 7 width=19
Element Seqn Id St Int Rpt
ESQHESEQDFSQGPCPTVR Q9UHJ4 175 7 -
ESQHESEQDFSQGPCPTVR Q60565 179 7 -

Motif 8 width=11
Element Seqn Id St Int Rpt
SACYFTLKLKE Q9UHJ4 432 238 -
SACYFTLKLKE Q60565 436 238 -

Motif 9 width=14
Element Seqn Id St Int Rpt
YARSIMEMLRLKGR Q9UHJ4 472 29 -
YARSIMEMLRLKGR Q60565 476 29 -
Final Motifs
Motif 1  width=15
Element Seqn Id St Int Rpt
FCSEGEGEPLALGDC P97557 29 29 -
FCSEGEGEPLALGDC Q9UHJ4 26 26 -
FCSEGEGEPLALGDC Q60565 30 30 -

Motif 2 width=16
Element Seqn Id St Int Rpt
GGSRFVLSQQALSCFP P97557 49 5 -
GGSRFVLSQQALSCFP Q9UHJ4 46 5 -
GGSRFVLSQQALSCFP Q60565 50 5 -

Motif 3 width=15
Element Seqn Id St Int Rpt
PSPLELCDDANPVDN P97557 88 23 -
PSPLELCDDANPVDN Q9UHJ4 85 23 -
PSPLELCDDANPVDN Q60565 89 23 -

Motif 4 width=14
Element Seqn Id St Int Rpt
GRLHVMEQLCALSF P97557 123 20 -
GRLHVMEQLCALSF Q9UHJ4 120 20 -
GRLHVMEQLCALSF Q60565 124 20 -

Motif 5 width=19
Element Seqn Id St Int Rpt
QEIQYWGIDELSIDSCCRD P97557 138 1 -
QEIQYWGIDELSIDSCCRD Q9UHJ4 135 1 -
QEIQYWGIDELSIDSCCRD Q60565 139 1 -

Motif 6 width=14
Element Seqn Id St Int Rpt
RYFRRKELSETLDF P97557 157 0 -
RYFRRKELSETLDF Q9UHJ4 154 0 -
RYFRRKELSETLDF Q60565 158 0 -

Motif 7 width=19
Element Seqn Id St Int Rpt
ESQHESEQDFSQGPCPTVR P97557 178 7 -
ESQHESEQDFSQGPCPTVR Q9UHJ4 175 7 -
ESQHESEQDFSQGPCPTVR Q60565 179 7 -

Motif 8 width=11
Element Seqn Id St Int Rpt
SACYFTLKLKE P97557 435 238 -
SACYFTLKLKE Q9UHJ4 432 238 -
SACYFTLKLKE Q60565 436 238 -

Motif 9 width=14
Element Seqn Id St Int Rpt
YARSIMEMLRLKGR P97557 475 29 -
YARSIMEMLRLKGR Q9UHJ4 472 29 -
YARSIMEMLRLKGR Q60565 476 29 -