A key protein involved in triggering the immune response against pathogens is described in a paper published online on April 02, 2006, by Nature. The immune response relies on the movement of calcium ions through specific CRAC channels in T cells. However, CRAC channel function is defective in patients with hereditary severe combined immune deficiency (SCID) syndrome.
Anjana Rao and her colleagues set out to identify the underlying genetic defect in SCID patients using a combination of two unbiased genome-wide approaches: single-nucleotide polymorphism arrays and a Drosophila RNA interference screen. Both methods identified a protein called Orai1. The authors show that SCID patients are homozygous for a mutation in the gene encoding Orai1. When wild-type Orai1 is expressed in T cells from SCID patients, CRAC channel function is restored. The authors propose that Orai1 is either an essential regulator or a component of the CRAC channel complex.
Anjana Rao (Harvard Medical School & CBR Institute for Biomedical Research, Boston, MA, USA)
(C) Nature press release.
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