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PR01377

Identifier
CLAUDIN1  [View Relations]  [View Alignment]  
Accession
PR01377
No. of Motifs
4
Creation Date
27-JUL-2000
Title
Claudin-1 signature
Database References
PRINTS; PR01077 CLAUDIN
Literature References
1. TSUKITA, S. AND FURUSE, M.
Occuldin and claudins in tight-junction strands: leading or supporting
players?
TRENDS CELL BIOL. 9 268-273 (1999).
 
2. FURUSE, M., FUJITA, K., HIIRAGI, T., FUJIMOTO, K. AND TSUKITA, S.
Claudin-1 and -2: novel integral membrane proteins localizing at tight 
junctions with no sequence similarity to occludin.
J.CELL BIOL. 141 1539-1550 (1998).
 
3.FURUSE, M., SASAKI, H., FUJIMOTO, K. AND TSUKITA, S.
A single gene product, claudin-1 or -2, reconstitutes tight junction 
strands and recruits occludin in fibroblasts.
J.CELL BIOL. 143 391-401 (1998).
 
4. MORITA, K., FURUSE, M., FUJIMOTO, K. AND TSUKITA, S.
Claudin multigene family encoding four-transmembrane domain protein
components of tight junction strands.
PROC.NATL.ACAD.SCI.U.S.A. 96 511-516 (1999).
 
5. SWISSHELM, K., MACHL, A., PLANITZER, S., ROBERTSON, R., KUBBIES, M. AND
HOSIER, S.
SEMP1, a senescence-associated cDNA isolated from human mammary epithelial
cells, is a member of an epithelial membrane protein superfamily.
GENE 226 285-295 (1999).

Documentation
Tight junctions (TJs) are specialised membrane domains found at the most 
apical region of polarised epithelial and endothelial cells. They create a 
primary barrier, preventing paracellular transport of solutes and 
restricting lateral diffusion of membrane lipids and proteins. They also 
act as diffusion barriers within plasma membranes, creating and maintaining
apical and basolateral membrane domains.
 
Recently, the molecular architecture of tight junctions has begun to be
elucidated. One group of proteins thought to be major components of TJs 
is the claudin family [1]. Immunofluorescence studies have shown that 
claudins are targeted to and incorporated into tight junctions [2]. 
Furthermore, when claudins are introduced into cells that lack tight 
junctions, networks of strands and grooves form at cell-cell contact sites 
that closely resemble native TJs [3].
 
The claudin protein family is encoded by at least 17 human genes, with many
homologues cloned from other species. Tissue distribution patterns for the 
claudin family members are distinct. Claudin-1 and -2, for example, are 
expressed at high levels in the liver and kidney, whereas claudin-3 mRNA is
detected mainly in the lung and liver [2,4]. This suggests that multiple 
claudin family members may be involved in tight junction strand formation 
in a tissue-dependent manner.
 
Hydropathy analysis suggests that all claudins share a common transmembrane
(TM) topology. Each family member is predicted to possess four TM domains 
with intracellular N- and C-termini. Although their C-terminal cytoplasmic 
domain sequences vary, most claudin family members share a common motif of 
-Y-V in this region. This has been postulated as a possible binding motif 
for PDZ domains of other tight junction-associated membrane proteins, 
such as ZO-1.
 
Claudin-1 was the first member of the claudin family to be identified as
a tight junction component [2]. The human isoform of claudin-1 was 
originally termed senescence-associated epithelial membrane protein 1 
(SEMP1) [5], but has since been reclassified. 
 
CLAUDIN1 is a 4-element fingerprint that provides a signature for claudin-1
proteins. The fingerprint was derived from an initial alignment of 2 
sequences: the motifs were drawn from conserved loop and C-terminal regions,
focusing on those sections that characterise claudin-1 and distinguish it
from other family members - motif 1 falls in the intracellular loop; 
motifs 2 and 3 reside within in the second extracellular loop; and motif 4
lies in the cytoplasmic C-terminal region. A single iteration on SPTR37_10f
was required to reach convergence, no further sequences being identified
beyond the starting set.
Summary Information
2 codes involving  4 elements
0 codes involving 3 elements
0 codes involving 2 elements
Composite Feature Index
42222
30000
20000
1234
True Positives
O88551        O95832        
Sequence Titles
O88551      CLAUDIN-1 - MUS MUSCULUS (MOUSE).             
O95832 SENESCENCE-ASSOCIATED EPITHELIAL MEMBRANE PROTEIN - HOMO SAPIENS (HUMAN).
Scan History
SPTR37_10f 1  150  NSINGLE    
Initial Motifs
Motif 1  width=12
Element Seqn Id St Int Rpt
MKCLEDDEVQKM O95832 105 105 -
MRCLEDDEVQKM O88551 105 105 -

Motif 2 width=8
Element Seqn Id St Int Rpt
YGNRIVQE O95832 140 23 -
YGNRIVQE O88551 140 23 -

Motif 3 width=8
Element Seqn Id St Int Rpt
MTPVNARY O95832 152 4 -
LTPINARY O88551 152 4 -

Motif 4 width=15
Element Seqn Id St Int Rpt
YPTPRPYPKPAPSSG O95832 193 33 -
YPTPRPYPKPTPSSG O88551 193 33 -
Final Motifs
Motif 1  width=12
Element Seqn Id St Int Rpt
MKCLEDDEVQKM O95832 105 105 -
MRCLEDDEVQKM O88551 105 105 -

Motif 2 width=8
Element Seqn Id St Int Rpt
YGNRIVQE O95832 140 23 -
YGNRIVQE O88551 140 23 -

Motif 3 width=8
Element Seqn Id St Int Rpt
MTPVNARY O95832 152 4 -
LTPINARY O88551 152 4 -

Motif 4 width=15
Element Seqn Id St Int Rpt
YPTPRPYPKPAPSSG O95832 193 33 -
YPTPRPYPKPTPSSG O88551 193 33 -