butyrophilin-like protein 2; BTL-II (BTNL2)

Function

• negative regulator of T-cell proliferation

Structure

• belongs to the immunoglobulin superfamily, BTN/MOG family
• contains 3 Ig-like V-type domains (immunoglobulin-like)

Compartment

• membrane; single-pass type 2 membrane protein
• isoform 2 is present in the nuclear membranes, vesicle membranes & plasma membranes
• isoform 3 (form associated with risk for sarcoidosis)
  • found in cytoplasmic vesicle structures
  • not membrane bound

Alternative splicing

named isoforms=6

Expression

• expressed in brain, heart, kidney, liver, pancreas, ovary, leukocyte, small intestine, testis & thymus
• induced by proinflammatory cytokines such as TNF & IL1B

Pathology

• genetic variation in BTNL2 is a cause of susceptibility to sarcoidosis type 2
  • a nucleotide transition affecting a splice donor site results in the use of an alternative splice site & the production of isoform 3
    • individuals expressing isoform 3 have a higher risk for sarcoidosis

More general terms

• secreted protein
• immunoglobulin superfamily protein
• human longevity protein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=56244
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:56244
• OMIM: https://mirror.omim.org/entry/606000
• OMIM: https://mirror.omim.org/entry/612387
• UniProt: http://www.uniprot.org/uniprot/Q9UIR0.html