B-cell linker

The adapter protein BLNK (B cell left protein and SLP -65 or BASH ) is a protein that is expressed in B cells of vertebrates, where it is involved in the signal line of the B-cell receptor. Mutations in the human BLNK gene are responsible for an uncommon form of agammaglobulinemia.

BLNK is associated with the B-cell receptor and ensures after stimulation of this receptor, the generation of a complex of various signaling proteins. Among them are about Bruton's tyrosine kinase and phospholipase C -gamma. BLNK has an atomic mass of 65 kilo - daltons and consists of a N-terminal region with five tyrosine residues, a central region with a plurality of Bindemotifen for SH3 domains and an SH2 domain at the C -terminus.

In cell lines has been shown that BLNK is responsible for the activation of phospholipase C -gamma, and thus for the generation of a calcium signal ( increase of the calcium ion concentration in the cell) after stimulation of the B cell receptor. BLNK itself is phosphorylated by the kinase Syk and thus activated.

Knockout mice lacking BLNK showing an erroneous B-cell development. The number of mature B cells is significantly reduced in these mice. Most B- cell precursors do not come via the pre-B cell stage addition. At this stage, a preform of the B- cell receptor for the first time is expressed. Another block of the B- cell development occurs in immature B cells. The BLNK B -deficient cells exhibit, in analogy to experiments with cell lines, a decreased calcium ion signal.

T cells expressing SLP -76, a similar protein that is functionally but not completely analogous. SLP-76 knock-out mice exhibit approximately a complete block in T cell development.

Protein isoform Human Genome Organisation Bruton's tyrosine kinase Immunity (journal)
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