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PR01605

Identifier
KCNE2CHANNEL  [View Relations]  [View Alignment]  
Accession
PR01605
No. of Motifs
4
Creation Date
12-SEP-2001
Title
KCNE voltage-gated K+ channel beta-2 subunit signature
Database References
PRINTS; PR00168 KCNECHANNEL
Literature References
1. MILLER, C.
An overview of the potassium channel family.
GENOME BIOL. 1(4) 1-5 (2000).
 
2. CONLEY, E.C. AND BRAMMAR, W.J.
MinK.
IN THE ION CHANNEL FACTSBOOK, VOLUME IV, ACADEMIC PRESS, 1999, PP.703-767.
 
3. ABBOT, G.W., SESTI, F., SPLAWSKI, I., BUCK, M.E., LEHMANN, M.H., TIMOTHY,
K.W., KEATING, M.T. AND GOLDSTEIN, S.A.N.
MiRP1 forms IKr potassium channels with HERG and is associated with cardiac
arrhythmia.
CELL 97 175-187 (1999).

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].
 
Some types of K+ channel are closed at the resting potential of the cell,
but open on membrane depolarisation, and are thus known as voltage-gated 
channels. Each of these types of channel typically comprises 4 pore-forming
alpha subunits that may associate with one of a number of different types of
beta subunit. Two types of beta subunit (KCNE and KCNAB) are presently known
to associate with voltage-gated alpha subunits (Kv, KCNQ and eag-like).
However, not all combinations of alpha and beta subunits are possible.
 
The KCNE family of K+ channel subunits are membrane glycoproteins that 
possess a single transmembrane (TM) domain. They share no structural 
relationship with the alpha subunit proteins, which possess pore forming 
domains. The subunits appear to have a regulatory function, modulating the 
kinetics and voltage dependence of the alpha subunits of voltage-dependent
K+ channels [2]. KCNE subunits are formed from short polypeptides of ~130
amino acids, and are divided into five subfamilies: KCNE1 (MinK/IsK),
KCNE2 (MiRP1), KCNE3 (MiRP2), KCNE4 (MiRP3) and KCNE1L (AMMECR2).
 
KCNE2 subunits associate with the eag-like HERG alpha subunits, which are
the pore-forming subunits of cardiac IKr channels. Channels formed solely
from HERG subunits display similar properties to native IKr channels;
however, they differ in their gating and single channel conductance. 
Channels formed from both KCNE2 and HERG exhibit properties that are 
identical to those seen in native IKr channels. Three mutations in the KCNE2
gene are associated with long QT syndrome and ventricular fibrillation. 
These mutations result in channels that open slower and close more rapidly,
the net effect being a reduced K+ current [3].
 
KCNE2CHANNEL is a 4-element fingerprint that provides a signature for the 
KCNE voltage-gated K+ channel beta-2 subunit. The fingerprint was derived 
from an initial alignment of 2 sequences: the motifs were drawn from
conserved regions spanning the N- and C-terminal portions of the alignment,
focusing on those sections that characterise the KCNE2 subunits but 
distinguish them from the rest of the KCNE family - motifs 1-3 lie in the 
extracellular N-terminus; and motif 4 resides in the cytoplasmic C-terminus.
Two iterations on SPTR39.22_17.3f were required to reach convergence, at 
which point a true set comprising 3 sequences was identified.
Summary Information
3 codes involving  4 elements
0 codes involving 3 elements
0 codes involving 2 elements
Composite Feature Index
43333
30000
20000
1234
True Positives
MIR1_HUMAN    MIR1_RAT      Q9D808        
Sequence Titles
MIR1_HUMAN  MINIMUM POTASSIUM ION CHANNEL-RELATED PEPTIDE 1 (MIRP1) (MINK-RELATED PEPTIDE 1) - Homo sapiens (Human). 
MIR1_RAT MINIMUM POTASSIUM ION CHANNEL-RELATED PEPTIDE 1 (MIRP1) (MINK-RELATED PEPTIDE 1) - Rattus norvegicus (Rat).
Q9D808 2200002I16RIK PROTEIN - Mus musculus (Mouse).
Scan History
SPTR39.22_17.3f 2  200  NSINGLE    
Initial Motifs
Motif 1  width=15
Element Seqn Id St Int Rpt
TQTLEDAFKKVFITY MIR1_RAT 8 8 -
TQTLEDVFRRIFITY MIR1_HUMAN 8 8 -

Motif 2 width=14
Element Seqn Id St Int Rpt
MDSWRRNTTAEQQA MIR1_RAT 23 0 -
MDNWRQNTTAEQEA MIR1_HUMAN 23 0 -

Motif 3 width=12
Element Seqn Id St Int Rpt
LQARVDAENFYY MIR1_RAT 37 0 -
LQAKVDAENFYY MIR1_HUMAN 37 0 -

Motif 4 width=13
Element Seqn Id St Int Rpt
SQILHLEDSKATI MIR1_RAT 98 49 -
SQILNLEESKATI MIR1_HUMAN 98 49 -
Final Motifs
Motif 1  width=15
Element Seqn Id St Int Rpt
TQTLEDAFKKVFITY MIR1_RAT 8 8 -
TQTLEDAFKKIFITY Q9D808 8 8 -
TQTLEDVFRRIFITY MIR1_HUMAN 8 8 -

Motif 2 width=14
Element Seqn Id St Int Rpt
MDSWRRNTTAEQQA MIR1_RAT 23 0 -
MDSWRRNTTAEEQA Q9D808 23 0 -
MDNWRQNTTAEQEA MIR1_HUMAN 23 0 -

Motif 3 width=12
Element Seqn Id St Int Rpt
LQARVDAENFYY MIR1_RAT 37 0 -
LQARVDAENFYY Q9D808 37 0 -
LQAKVDAENFYY MIR1_HUMAN 37 0 -

Motif 4 width=13
Element Seqn Id St Int Rpt
SQILHLEDSKATI MIR1_RAT 98 49 -
SQILHLEDSKATI Q9D808 98 49 -
SQILNLEESKATI MIR1_HUMAN 98 49 -