CD157 BST1 (bone marrow stromal cell antigen 1), BP-3/IF-7 [murine], Mo5, cADPr hydrolase 2
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
GPI anchor
Granulocyte
Monocyte
Myelomonocytic cell
Bone Marrow
Stromal Cell
Leukemia cell
Endothelial Cell
Synovial Cell
Dendritic Cell
Follicular Cell
Lymph Node
Peyer's Patch
T Cell
B Cell
Progenitor Cell
Peripheral blood
Macrophage
42 / 42
50 / 50

Expression
CD157 is expressed on granulocytes and monocytes in the peripheral blood of healthy donors and macrophages differentiated in vitro.  This is a marker molecule for B cell progenitors and macrophages in the mouse with mAb BP-3. Surface expression of CD157 on lymphoid progenitor cells appear prior to the gene rearrangement of M heavy chain and TCRb chain in the mouse.  In the T lineage, the expression of CD157 is restricted to CD44-CD25+ and CD44-CD25- fractions of CD3-CD4-CD8 T progenitors.  In the B lineage, the expression of CD157 is downregulated at the stage of mature B cell expressing surface IgD.  Expression is on bone marrow stromal cell lines, myelomonocytic leukemia, human umbilical vein endothelial cells, rheumatoid arthritis-derived synovial cell lines and follicular dendritic cell lines.  CD157 is also expressed in the mouse by the reticular cells of peripheral lymphoid tissues such as spleen, lymph nodes and Peyers' patches.



Structure
MOLECULAR FAMILY NAME:  Belongs to the ADP-ribosyl cyclase family.

CD157 is a 318 aa GPI-anchored molecule.  It contains signal sequence containing 10 cysteines which shows homology with the structure of CD38.

MOLECULAR MASS
Cell Type Unreduced Reduced Comment
Bone marrow stroma 42-45 kDa 42-45 kDa
Synovial cells 42-45 kDa 42-45 kDa
Monocytes (by anti-Mo5) 50 kDa 50 kDa

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION

CD157 has 4 N-glycosylation sites.

Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH CD157 

CD157 is a bifunctional enzyme and uses NAD and cyclic ADP-ribose as substrates.


Function
CD157 functions in pre-B cell growth.  CD157 may also function as a signaling molecule because cross-linking by antibody induces tyrosine phosphorylation of a 130 kDa cytoplasmic protein.  CD157 is a sister molecule of CD38 with identical ectoenzyme activity.  CD157 has a distribution complementary to that of CD38.  CD157 supports the growth of a pre-B cell line, CD34.  Anti-CD157 mAb IF-7 has synergistic effects on anti-CD3-induced growth of T progenitor cells and facilitates the development of ab TCR+ cells in fetal thymic organ culture system. 

BIOCHEMICAL ACTIVITY

CD157 has ADP-ribosyl cyclase and cyclic ADP-ribose hydrolase activities.  

DISEASE RELEVANCE AND FUNCTION OF CD157 IN INTACT ANIMAL

The potential diagnostic value is due to elevaled CD157 on rheumatoid arthritis-derived bone marrow stromal cell lines and in serum of a subset of rheumatoid arthritis patients with severe disease.  The polyclonal B cell abnormalities in rheumatoid arthritis may be, in part, attributed to CD157 overexpression in the stromal cell population.  High levels of serum soluble CD157 are detected in 13% of cases with severe rheumatoid arthritis.  Knockout mice have impaired B cell function, suggesting CD157 is involved in B cell development.  This consistent with the demonstrated function of bone marrow stromal cell CD157 in supporting pre-B cell growth.  CD157 is also differentially expressed in the myeloid leukemias.

Comments
MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD157: No information.

SUBSTRATES
Molecule Comment
NAD
Cyclic ADP-ribose

ENZYMES WHICH MODIFY CD157: No information.

ADDITIONAL INSIGHTS

Crosslinking of CD157 by polyclonal anti-CD157 antibody induced tyrosine phosphorylation of a 130 kDa.  Protein in human myelomonocytic cell lines, U937 and THP-1 suggests the functional role of CD157 as a receptor.  Anti-murine pre-T cell mAb IF-7 also recognizes CD157 BST-1/BP-3.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 683Q10588
Antibodies

Revised June 25, 2008


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