Nonfunctional Orai1 N-truncation mutants display a significant reduction in STIM1 binding.
a, intensity plots representing the localization of STIM1 233–474 L251S across the cell when co-expressed with Orai1 ΔN1–74, Orai1 ΔN1–76, Orai1 ΔN1–78, Orai1 ΔN1–88, and Orai1 ΔC-term when compared with wild-type Orai1. a. u., arbitrary units. b, intensity plots representing the localization of STIM1 233–474 (OASF) across the cell when co-expressed with Orai1 ΔN1–74, Orai1 ΔN1–76, and Orai1 ΔN1–78 when compared with wild-type Orai1. c, binding curve fitted to a one-site binding model for YFP-STIM1 233–485 from a HEK293 cell lysate together with Orai1 NT(aa70–91) or Orai1 NT(aa77–91) in comparison with YFP from HEK293 cell lysate together with Orai1 NT(aa70–91), obtained from thermophoresis experiments.