Mechanistic calcium-mediated feedback controlling proton pump activity for osmoregulation

Develop a quantitative and mechanistic model of the calcium-mediated feedback proposed to regulate proton pump activity on contractile-vacuole-like membrane tubes or vacuoles in response to membrane tension or cytosolic calcium, and determine the degree of parameter tuning required to achieve robust osmoregulation in freshwater conditions.

Background

To enable active regulation of cell volume, the authors suggest a feedback mechanism in which mechano-sensitive calcium channels trigger calcium influx that modulates proton pump activity on the vacuole or tubes. Such a mechanism could allow the system to counterbalance passive osmotic influx by actively pumping water out.

While the qualitative idea is outlined with biological precedents, the detailed formulation and analysis—linking calcium dynamics, pump regulation, and system performance—are not developed here and are explicitly deferred.