Honors Theses
Advisor
Carissa Krane
Department
Biology
Publication Date
Spring 4-2014
Document Type
Honors Thesis
Abstract
Cope’s gray treefrog Hyla chrysoscelis, accumulates and distributes glycerol as a cryoprotectant in anticipation of freezing. Transmembrane glycerol and water flux in H. chysoscelis erythrocytes likely occurs through HC-3, an ortholog of mammalian aquaporin 3. HC-3 protein is in higher abundance and is preferentially localized to the plasma membrane in RBCs from cold-acclimated treefrogs as compared to warmacclimated animals. It is hypothesized that neuroendocrine agonists via receptor mediated second messenger pathways integrate signals derived from fasting, dehydration, diurnal, and/or temperature changes during cold-acclimation to regulate HC-3 expression as part of the mechanism of freeze tolerance. In this study, cultured H. chrysoscelis erythrocytes were exposed to 1 uM epinephrine for 30 and 60 minutes. Native HC-3 expression increased 3 fold at 30 minutes and 5.5-fold at 60 minutes relative to controls, whereas glycosylated HC-3 expression increased by 1.1-fold at 30 minutes and by 2 -fold at 60 minutes relative when exposed to epinephrine. Moreover, epinephrine treatment resulted in membrane localization as compared to cytosolic distribution in control cells. Erythrocytes pre-treated with Calphostin C, a PKC inhibitor, showed no HC-3 membrane localization, and native HC-3 expression was reduced by 5% relative to controls and 3- fold relative to epinephrine-treated cells. Thus, epinephrine begins a PKC-dependent mechanism that results in an increase in HC-3 abundance, HC-3 membrane localization, and enhanced glycosylation in erythrocytes. These regulatory mechanisms are consistent with the in vivo regulation of HC-3 expression observed in erythrocytes from coldacclimated treefrogs.
Permission Statement
This item is protected by copyright law (Title 17, U.S. Code) and may only be used for noncommercial, educational, and scholarly purposes.
Keywords
Undergraduate research
Disciplines
Biology | Life Sciences
eCommons Citation
Ratycz, Connor J., "Epinephrine Regulates Aquaglyceroporin HC-3 Expression and Subcellular Localization in Cultured Erythrocytes from the Freeze-Tolerant Treefrog, Hyla chrysoscelis" (2014). Honors Theses. 33.
https://ecommons.udayton.edu/uhp_theses/33
