ORAI Detection Set

Antigen stimulation of immune cells triggers Ca++ entry through Ca++ release-activated Ca++ (CRAC) channels. The ORAI family is a recently identified set of proteins that are essential components of these CRAC channels. A missense mutation in the ORAI1 protein in humans is the cause of one form of hereditary severe combined immune deficiency (SCID) which results in ablated T-cell Ca++ entry. It has been suggested that ORAI1 functions as a highly selective Ca++ plasma membrane channel that is gated through interactions with the stromal interaction molecule 1 (STIM1), the store-activated endoplasmic reticulum Ca++ sensor. Like ORAI1, ORAI2 also functions as a highly selective Ca++ plasma membrane channel that is gated through interactions with STIM1, although at a lesser efficacy than ORAI1. Although ORAI3 can also function as Ca++ plasma membrane channel, ORAI3 channels failed to produce detectable Ca++ selective currents in cells co-transfected with ORAI3 and STIM1, indicating that ORAI3 channels undergo a lesser degree of depotentiation than ORAI1 or ORAI2. Na+ currents through ORAI1, 2 and 3 channels were equally inhibited by extracellular Ca++, indicating that each have similar affinities for Ca++ within the selectivity filter. STIM1, in its function as a Ca++ sensor and an activator of CRAC channels, migrates to the plasma membrane from endoplasmic reticulum-like sites which act as cellular Ca++ stores. A related molecule, STIM2, inhibits the STIM1-mediated store-operated Ca++ entry, and can form complexes with STIM1, suggesting these two proteins may play a coordinated role in controlling Ca++ entry. The ORAI antibodies are predicted to have no cross-reactivity to the other ORAI proteins. Similarly, the STIM antibodies will not cross-react with the other STIM protein.

For images please see PDF data sheet

PBS containing 0.02% sodium azide.

Antibody 1 mg/mL

Rabbit polyclonal antibodies were raised against peptides corresponding to amino acid sequences from each of the corresponding proteins.

Liquid

Antibodies are supplied as affinity chromatography purified IgG.

Optimal dilutions for each application to be determined by the researcher.