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PR01679

Identifier
KIR7CHANNEL  [View Relations]  [View Alignment]  
Accession
PR01679
No. of Motifs
4
Creation Date
13-MAR-2002
Title
Kir7 inward rectifier K+ channel signature
Database References
PRINTS; PR00169 KCHANNEL; PR01320 KIRCHANNEL
Literature References
1. MINOR, D.L., JR., MASSELLING, S.J., JAN, Y.N. AND JAN, L.Y.
Transmembrane structure of an inwardly rectifying potassium channel.
CELL 96 879-891 (1999).
 
2. DOUPNIK, C.A., DAVIDSON, N. AND LESTER, H.A.
The inward rectifier potassium channel family.
CURR.OPIN.NEUROBIOL. 5 268-277 (1995).
 
3. REIMANN, F. AND ASHCROFT, F.M.
Inwardly rectifying potassium channels.
CURR.OPIN.CELL BIOL. 11 503-508 (1999).
 
4. DORING, F. AND KARSCHIN, A.
Genomic structure and promoter analysis of the rat kir7.1 potassium channel
gene(Kcnj13).
FEBS LETT. 20 483 93-98 (2000).
 
5. DERST, C., DORING, F., PREISIG-MULLER, R., DAUT, J., KARSCHIN, A., JECK,
N., WEBER, S., ENGEL, H. AND GRZESCHIK, K.H.
Partial gene structure and assignment to chromosome 2q37 of the human
inwardly rectifying K+ channel (Kir7.1) gene (KCNJ13).
GENOMICS 15 54(3) 560-563 (1998).
 
6. NAKAMURA, N., SUZUKI, Y., SAKUTA, H., OOKATA, K., KAWAHARA, K. AND 
HIROSE, S.
Inwardly rectifying K+ channel Kir7.1 is highly expressed in thyroid 
follicular cells, intestinal epithelial cells and choroid plexus epithelial
cells: implication for a functional coupling with Na+,K+-ATPase.
BIOCHEM.J. 342(2) 329-336 (1999).

Documentation
Potassium channels are found in virtually all cell types. Their pore-
forming subunits fall into three structural families, i.e. those possessing
six, four and two transmembrane (TM) domains. The six-TM domain K+ channels
can be further subdivided into six families: the voltage-gated K+ channels
(Kv), the KCNQ channels, the eag-like K+ channels, and three Ca2+-activated
K+ channels. Inwardly-rectifying K+ channels (Kir) are the principal class
of two-TM domain K+ channels, and the recently-discovered two-pore domain
K+ channels, make up a family of four-TM domain K+ channels.
                  
Inwardly rectifying potassium channels (Kir) are responsible for regulating
diverse processes including: cellular excitability, vascular tone, heart
rate, renal salt flow, and insulin release [1]. To date, around twenty
members of this superfamily have been cloned, which can be grouped into six
families by sequence similarity - these are designated Kir1.x-7.x [2,3].
                  
Cloned Kir channel cDNAs encode proteins of between ~370-500 residues,
containing two predicted TM domains, with the characteristic K+ channel
pore-forming domain located between them. Both N- and C-termini are thought
to be cytoplasmic, and the N-terminus lacks a signal sequence. It is thought 
that four Kir subunits assemble to form a tetrameric channel complex, which
may be hetero- or homomeric [1].
 
The KCNJ13 gene encodes a Kir7 alpha subunit that is predominantly expressed
in the brain. It is also present in intestinal epithelial cells, thyroid
follicular cells, spinal cord, kidney and stomach [4,5], suggesting a role
in the regulation of the ion-transporting functions of these specialised
cells. The unique properties of Kir7 make it a strong candidate for the low-
conductance K+ channel that is coupled to Na+K+-ATPase by recycling K+ [6]. 
 
KIR7CHANNEL is a 4-element fingerprint that provides a signature for the
Kir7 inward rectifier K+ channel. The fingerprint was derived from an
initial alignment of 3 sequences: the motifs were drawn from conserved
regions spanning virtually the full alignment length, focusing on those 
sections that characterise Kir7 but distinguish it from other Kir channel
subtypes - motifs 1-3 span the N-terminus; and motif 4 resides at the
C-terminus. A single iteration on SPTR40_18f was required to reach
convergence, no further sequences being identified beyond the starting set.
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
IRKD_CAVPO    IRKD_RAT      O60928        
Sequence Titles
IRKD_CAVPO  Inward rectifier potassium channel 13 (Potassium channel, inwardly rectifying, subfamily J, member 13) (Inward rectifier K+ channel Kir7.1) - Cavia porcellus (Guinea pig). 
IRKD_RAT Inward rectifier potassium channel 13 (Potassium channel, inwardly rectifying, subfamily J, member 13) (Inward rectifier K+ channel Kir7.1) - Rattus norvegicus (Rat).
O60928 INWARD RECTIFIER POTASSIUM CHANNEL KIR 7.1 (INWARDLY RECTIFYING POTASSIUM CHANNEL KIR7.1) - HOMO SAPIENS (HUMAN).
Scan History
SPTR40_18f 1  250  NSINGLE    
Initial Motifs
Motif 1  width=20
Element Seqn Id St Int Rpt
MDSSNCKVIAPLLSQRYRRM O60928 1 1 -
MDSRNCKVNAPLLSQRYRRM IRKD_RAT 1 1 -
MESSNCKVITPLLSQRHRRM IRKD_CAVPO 1 1 -

Motif 2 width=16
Element Seqn Id St Int Rpt
TKDGHSTLQMDGAQRG O60928 22 1 -
TKDGHSTLQMDGAQRG IRKD_RAT 22 1 -
TKDGHSTLQTDGAPRG IRKD_CAVPO 22 1 -

Motif 3 width=18
Element Seqn Id St Int Rpt
RFTDTAVVAHMDGKPNLI O60928 171 133 -
RFTDLAVVAHKDGKPNLI IRKD_RAT 171 133 -
RFTDLAVVAHRDGKPNLI IRKD_CAVPO 171 133 -

Motif 4 width=17
Element Seqn Id St Int Rpt
NGQSIDNFQISETGLTE O60928 344 155 -
NGQSIDNFQIAETGLTE IRKD_RAT 344 155 -
NGQSIDNFQISETGLTE IRKD_CAVPO 344 155 -
Final Motifs
Motif 1  width=20
Element Seqn Id St Int Rpt
MDSSNCKVIAPLLSQRYRRM O60928 1 1 -
MDSRNCKVNAPLLSQRYRRM IRKD_RAT 1 1 -
MESSNCKVITPLLSQRHRRM IRKD_CAVPO 1 1 -

Motif 2 width=16
Element Seqn Id St Int Rpt
TKDGHSTLQMDGAQRG O60928 22 1 -
TKDGHSTLQMDGAQRG IRKD_RAT 22 1 -
TKDGHSTLQTDGAPRG IRKD_CAVPO 22 1 -

Motif 3 width=18
Element Seqn Id St Int Rpt
RFTDTAVVAHMDGKPNLI O60928 171 133 -
RFTDLAVVAHKDGKPNLI IRKD_RAT 171 133 -
RFTDLAVVAHRDGKPNLI IRKD_CAVPO 171 133 -

Motif 4 width=17
Element Seqn Id St Int Rpt
NGQSIDNFQISETGLTE O60928 344 155 -
NGQSIDNFQIAETGLTE IRKD_RAT 344 155 -
NGQSIDNFQISETGLTE IRKD_CAVPO 344 155 -