CD151 RAPH (Raph blood group), PETA-3 (platelet-endothelial tetra-span antigen 3), Tspan-24
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 3 glycoprotein, 4 span
Megakaryocyte
Platelet
Monocyte
Epithelial Cell
Endothelium
Hematopoietic Cell, Immature
Erythroid Cell
Skeletal muscle
T Cell
Erythrocyte
28 / 28
32 / 32

Expression
CD151 is expressed on endothelium, endosomes, in the intracellular pool in the perinuclear region and possibly on the Golgi/trans-Golgi network.  It is expressed on platelets, muscle, megakaryocytes, monocytes, immature hematopoietic cells only with some mAbs, epithelial cells activated T cells and erythroid cells with a higher level of expression than mature erythrocytes.



Structure
MOLECULAR FAMILY NAME: Belongs to the transmembrane-4 superfamily.

CD151 is a multi-pass type-3, 4 span 253 aa glycoprotein.  It contains an extracellular domain which contains 2 loops which are divergent between tetraspanin members, a 15 aa loop and a larger 109 aa loop which contains a N-glycosylation site, a transmembrane domain and a 16 aa short cytoplasmic domain which contains a 15 aa N-terminus and a 5 aa C-terminus.  CD151 is a cell surface glycoprotein that is known to complex with integrins and other transmembrane 4 superfamily proteins, also known as the tetraspanin family.  CD151 is characterized by the presence of 4 hydrophobic domains.  

MOLECULAR MASS
Cell Type Unreduced Reduced Comment
M07e cells 32 kDa 27 kDa

POST-TRANSCRIPTIONAL MODIFICATION OF CD151

No isoforms are detected.  A single 1.6 kb transcript is in different tissues.  Multiple alternatively spliced transcript variants have been described for CD151 with multiple polyadenylation sites.

POST-TRANSLATIONAL MODIFICATION

CD151 has 1 N-linked glycosylation site in the large extracellular loop between 3rd and 4th transmembrane passes.

Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH CD151

CD151 co-precipitates with β1 integrins including a3b1, a5b1and α6β4 with CD9 and CD181.

Function
CD151 mediates signal tranduction events that play a role in the regulation of cell development, activation, growth and motility.  CD151 is involved in cellular processes including cell adhesion and may regulate integrin trafficking and/or function.  This enhances cell motility, invasion and metastasis of cancer cells.  The CD151 mAb, 14A2.H1, activates platelets in vitro.  CD151 is co-precipitated with β1 integrins suggesting involvement in a complex.  F(ab')2 fragments of mAb 11B1.G4 cause homotypic adhesion of human erythroleukemia cell lines HEL and K562 and bring about platelet activation and aggregation.  The in vivo function of CD151 is not known but it appears to be part of the signaling complex of FcγRIIa and to modulate intregrin function.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD151 IN INTACT ANIMAL

CD151 is essential for the proper assembly of the glomerular and tubular basement membranes in the kidney.  Defects in CD151 are the cause of nephropathy with pretibial epidermolysis bullosa and deafness.  It has been suggested that there are epitope differences between CD151 on malgnant and normal cells.

Comments
MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD151: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD151: No information.

ADDITIONAL INSIGHTS

CD151 is an integrin associated protein and causes transmembrane signaling.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 977P48509
Antibodies
14A2.H1   View Reactivity

Revised June 25, 2008


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