FIGURE 4.

TPRV5 plasma membrane retention is regulated via lipid rafts. A, biotinylation of HEK293 cells expressing TRPV5 after filipin treatment, a representative blot is depicted. B, biotinylation of cells expressing TRPV5^N358Q after filipin treatment, a representative blot is depicted. C, relative cell surface expression, with or without filipin treatment (white and black bar, respectively) of TRPV5 (n = 6) or TRPV5^N358Q (n = 3) overexpressing cells; D, ⁴⁵Ca²⁺ uptake assay in the presence of filipin (n = 3). Filipin significantly increases Ca²⁺ uptake independent on the N-glycan of TRPV5 (white bar). E, ⁴⁵Ca²⁺ uptake assay in the presence of filipin and klotho or sialidase (n = 3). Klotho significantly increased TRPV5-dependent ⁴⁵Ca²⁺-uptake in the presence of flilipin, while sialidase treatment gave no additional effect. All data are presented as mean ± S.E.; *, p < 0.05, statistically significant.