Figure 9. Reconstitution of a [Ca²⁺]_e-sensitive NALCN Current in HEK293T Fibroblasts with CaSR, NALCN, and UNC80.

(A–C) Representative currents obtained with a voltage-ramp protocol (-100 mV to +100 mV in 1 sec, Vh = -20 mV) from non-transfected cells (A) or cells transfected with various combination of NALCN, UNC80, and CaSR, as indicated (B, C) in baths containing 1.2 mM Ca²⁺ (1.2 Ca) or 0.1 mM Ca²⁺ (0.1 Ca). All baths contained 155 mM Na⁺ except that NMDG⁺ was used to replace Na⁺ and K⁺ in the (NMDG, 0.1 Ca) baths. All transfections also included a constitutively active Src (Src529) to increase the percentage of cells expressing detectable current (see Experimental Procedures and (Lu et al., 2009)). (D) Averaged size of the increase of inward current (I_LCA, at -100 mV) upon lowering [Ca²⁺]_e from 1.2 mM to 0.1 mM (I_LCA). Cell number for each experiment is shown in parentheses. See also Figure S6.