Mechanisms for acid/base sensing and regulation in sharks
Funded by NSF IOS 1354181
Aerial view of leopard shark congregation in La Jolla Shores (credit: Dr. Andy Nosal)
Sharks are an excellent model to study acid/base sensing and regulation because they normally undergo large variations in their acid/base status, and because they control their blood acid/base status almost exclusively using their gills. These two characteristics make it easier to study physiology at the whole animal and cellular levels.
Underwater picture of a leopard shark swimming around La Jolla Shores (Credit: Dr. Martin Tresguerres)
Our goals are to characterize cellular mechanisms involved for secreting acid and base in gill cells, as well as potential molecular sensors of acid/base status. We are currently focusing in the cAMP pathway, in particular on the enzyme soluble adenylyl cyclase (sAC) which is an evolutionarily conserved pH/CO2/HCO3- sensor.
In addition to gill cells, we found that sAC is present in the nucleus of cells from diverse organs, and we are investigating the potential involvement of sAC in regulating gene expression. We work with leopard sharks (Triakis semifasciata), which is found around San Diego and congregates in La Jolla Shores every summer. We also work with local round rays (Urobatis halleri).
Microscopy picture of a leopard shark gill section showing immunolocalization of sodium/potassium ATPase (in red) and V-type proton ATPase (in green) credit: Roa et al. 2014)
- Tresguerres, M. and Parks, S. K. and Salazar, E. and Levin, L. R. and Goss, G. G. and Buck, J. 2010. Bicarbonate-sensing soluble adenylyl cyclase is an essential sensor for acid/base homeostasis. Proceedings of the National Academy of Sciences of the United States of America. 107:442-447. 10.1073/pnas.0911790107
- Roa, J. N., Munévar, C. L. and Tresguerres, M. 2014. Feeding induces translocation of vacuolar proton ATPase and pendrin to the membrane of leopard shark (Triakis semifasciata) mitochondrion-rich gill cells. Comparative Biochemistry and Physiology.