Figure 7.

Hypoxia increases agonist-induced Ca²⁺ mobilization by TPα; effect of C-terminal amino acid substitution mutation. HEK293T cells transfected with human wild-type TPα, or serine-to-alanine substitution mutants Ser324A, Ser329A or Ser331A were incubated for 48 h in hypoxic or normoxic conditions, followed by challenge with serial concentrations of agonist U46619. Absolute Ca²⁺ mobilization curves showing (A) differing effects of Ser324 substitution on agonist sensitivity in normoxic versus hypoxic conditions, relative to wild-type TP receptors; (B) effect of Ser329 substitution on hypoxia sensitivity of TP receptor-mediated Ca²⁺ response; and (C) effect of Ser331 substitution on hypoxic and normoxic TP agonist responses.