CD24; signal transducer CD24; small cell lung carcinoma cluster 4 antigen (CD24, CD24A)

Function

• modulates B-cell activation responses
• signaling could be triggered by the binding of a lectin-like ligand to the CD24 carbohydrates, & transduced by release of second messengers derived from the GPI-anchor
• promotes AG-dependent proliferation of B-cells, & prevents their terminal differentiation into antibody-forming cells
• interacts with LYN & FGR in a cell-type specific manner
• binds FRG in a small cell cancer line, LYN in the erythroleukemia cell line K562 & in Burkitt's lymphoma

Structure

• extensively O-glycosylated
• belongs to the CD24 family

Compartment

cell membrane; lipid-anchor, GPI-anchor

Expression

• B cells: expression is lost when primary B-cells are induced to differentiate in antibody-forming cells
• granulocytes
• kidney cells
• epithelial cells

Pathology

• positive staining in carcinomas:
  • high levels in small cell carcinoma
• pre-B ALL/LBL (most)
• B cell lymphomas (virtually all)
• plasma cells, multiple myeloma, T cells, monocytes, red blood cells & platelets stain negatively with antibody
• genetic variations in CD24 are associated with susceptibility to multiple sclerosis

More general terms

• CD antigen
• glypiated protein

Database

• UniProt: http://www.uniprot.org/uniprot/P25063.html
• OMIM: https://mirror.omim.org/entry/126200
• OMIM: https://mirror.omim.org/entry/600074
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=934