Studies on molecular mechanisms in calcium signaling and cellular energy consumption

Sammanfattning: Ion signaling plays fundamental role in cell survival. Na+ and Ca2+ are critical players in ion signaling. Cells spend the major amount of energy to maintain and regulate Na+ and Ca2+ gradients across the cell membrane. Any disruption in cellular energy consumption by plasma membrane ATPases affects ion signaling and vice versa. This thesis is a combination of four separate research studies. In the first study, We measured ATP consumption dynamics of Na+/K+-ATPase using a genetically encoded fluorescent indicator called Perceval HR. we demonstrate that PercevalHR is an excellent tool to visualize ATP:ADP in mammalian cells.In the second study, We studied the role of calcium signaling and TRP channels in angiotensin II type 1 receptor  signaling cascade. We prove that low inhibition of CaV1.2 with physiological and therapeutically relevant concentration of Angiotensin II up regulate AT1R signaling.In the third study, We studied the role of the TRPM5 channel in regulating insulin secretion, and cytoplasmic free calcium concentration in the rat β-cells by usingtriphenyl phosphine oxide, a selective inhibitor of the channel.In the fourth study, We tested whether, the genetically engineered human β-cell line (EndoC-BH1) could be used as models for studying Ca2+signaling in the context of Type II Diabetes. We found that the EndoC-BH1 cells could be a relevant model to study stimulus-secretion coupling and Ca2+ signaling in the human β-cells.