Carbon dioxide, pH and bicarbonate (CO2/pH/HCO3–) are essential for life because they affect chemical kinetics and protein structure and function; they also are substrates or products of respiration, photosynthesis and calcification. Although regulating these crucial processes surely relies on the ability to sense CO2/pH/HCO3– levels, the specific mechanisms remain practically unknown in aquatic organisms. Our research seeks to provide a link between metabolic and environmental acid/base stress and downstream physiological responses.
We seek to elucidate how aquatic organisms sense CO2/pH/HCO3–. We are currently focusing on the cAMP pathway, for example, we are investigating the enzyme “soluble adenylyl cyclase” (sAC), which directly activated by HCO3– to produce cAMP, and has proposed to be an evolutionarily conserved acid/base sensor. We are also investigating other novel chemosensory mechanisms and how the different signals get integrated to ultimately regulate cell and organismal physiology.
We have found that sAC is present in corals (Barott et al. 2013) as well as in several oyster and shark organs. We have also found that sAC is present in the nucleus of cells from some organisms. This suggests that sAC regulates gene expression in response to acid/base stress.
A related area of research is cellular mechanisms for ion transport, which are relevant for metabolism, acid/base regulation, calcification, nutrient absorption, and neuronal function, among other essential processes. We also investigate how this mechanisms are regulated, for example by the cAMP pathway.