T-cell surface glycoprotein CD1b; CD1b (CD1B)

Function

• antigen-presenting protein that binds self & non-self lipid & glycolipid antigens & presents them to T-cell receptors on natural killer cells
• heterodimer with B2M (beta-2-microglobulin)
• interacts with saposin C
• interaction with saposin C is required for the loading of bacterial lipid antigens onto CD1B in the lysosome

Structure

contains 1 Ig-like domain (immunoglobulin-like)

Compartment

• cell membrane
• endosome membrane, lysosome membrane
• subject to intracellular trafficking between the plasma membrane, endosomes & lysosomes
• localizes to cell surface lipid rafts
• during protein synthesis & maturation, CD1 family members bind endogenous lipids that are replaced by lipid or glycolipid antigens when the proteins are internalized & pass through endosomes or lysosomes, before trafficking back to the cell surface

Alternative splicing

named isoforms=2

Expression

• expressed on cortical thymocytes, on certain T-cell leukemias, & in various other tissues
• normal B cells, stain negative with antibody

Pathology

• positive immunohistochemical staining in:
  • myeloid leukemias
  • some B cell malignancies

More general terms

• CD1

Database

• UniProt: http://www.uniprot.org/uniprot/P29016.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=910
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:910
• OMIM: https://mirror.omim.org/entry/188360