CD231 TSPAN7(tetraspanin 7), TALLA-1 (T-cell acute lymphoblastic leukemia associated antigen 1), TM4SF2
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 3 glycoprotein, 4 span
Leukemia cell
Neuroblastoma cell
Brain Cell
Neuron
T Cell
Endothelial Cell
Lymphoblastoid cell
Myelocyte
32 / 32
150 / 150

Expression
CD231 is strongly expressed on T-cell acute lymphoblastic leukemic cells, neuroblastoma cells, normal brain neurons, neuronal tissues and on endothelial cells.  CD231 is not expressed on B cells or monocytes.  Expression is also found in acute myelocytic leukemia cells of some patients.


Structure
MOLECULAR FAMILY NAME: Belongs to the tetraspanin family.

CD231 is a multi-pass type-3, 4 span 244 aa glycoprotein.  It contains 2 extracellular domains which contains 2 unequal loops, a 16 aa small loop with 1 potential N-glycosylation site and a 101 aa larger loop with 4 glycosylation sites, 4 putative hydrophobic transmembrane domains and a cytoplasmic domain.  The 2 extracellular loops are divided by an EC1-proximal transmembrane domain of 19 aa followed by 11 intracellular residues and an EC2-proximal transmembrane domain region of 26 aa.  The 16 aa N-terminal cytoplasmic is separated from EC1 by a 24 aa transmembrane domain.  The 15 aa C-terminal intracellular cytoplasmic domain contains a tyrosine-based internationalization motif (YxxF) common to all tetraspanins.  a 21 aa transmembrane domain separates the C-terminal cytoplasmic domain from EC2.

MOLECULAR MASS
Cell Type Unreduced Reduced Comment
MOLT-4 150 kDa 32-45 kDa A polymer of 150 kDa under unreduced conditions
Jurkat 38-45 kDa
Brain tissue 150 kDa 32-45 kDa A polymer of 150 kDa under unreduced conditions

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION

CD231 has 4 potential N-glycosylation sites in the EC2 domain with 150 aa, 153 aa, 172 aa, and 183 aa respectively.  Treatment with N-glycanase reduces CD231 to a Mr of 27 kDa.


Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH CD231: No information.

Function
Originally CD231 was described as a specific marker for T-cell acute lymphoblastic leukemia specific antigen.  Its function is currently unknown but the protein mediates signal transduction events that may play a role in the regulation of cell development, proliferation, growth and motility.  This protein may have a role in the control of neurite outgrowth.  It is known to complex with integrins.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD230 IN INTACT ANIMAL

CD231 is highly expressed and is a specific marker and is a potential therapeutic agent in the treatment of T-cell acute lymphoblastic leukemia (TALL).  Ricin A-chain conjugates of mAb SN1 effectively kill TALL cells in vitro.  The conjugates suppress TALL tumors in nude mice.  Defects in CD231 is involved in X-linked mental retardation in which tetraspanin (TM4SF2) is inactivated by a translocation or poinjt mutations.  CD231 is also involved in neuropsychiatric diseases such as Huntington's chorea, fragile X syndrome (MRX58) and myotonic dystrophy (XLMR).  CD231 is inactivated by an X:2 balanced translocation and the following point mutations in exon 6 at the position 652 leading to a premature STOP G218 to X, and in exon 5 P172H.  CD231 can be potentially useful as an anti-tumor agent.

Comments
MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD231: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD231: No information.

ADDITIONAL INSIGHTS

Monoclonal anti-idiotypic antibody expressing the internal image of CD231 has been generated.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgen 7102P41732
Antibodies

Revised June 25, 2008


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