Abstract
Plasma membrane Cl-/HCO3- anion-exchange (AE) proteins contribute to regulation of intracellular pH (pHi). We characterized the transport activity and regulation by pHi of full-length AE3 and the cardiac isoform, AE3c, both of which are expressed in the heart. AE3c is an N-terminal variant of AE3. We also characterized AE1, AE2 and a deletion construct (AE3tr) coding for the common region of AE3 and AE3c. AE proteins were expressed by transient transfection of HEK-293 cells, and transport activity was monitored by following changes of intracellular pH or intracellular chloride concentration associated with anion exchange. Transport activities, measured as proton flux (mM H+˙min-1), were as follows: AE1, 24; AE2, 32; full-length AE3, 9; AE3c, 4 and AE3tr, 4. The wide range of transport activities is not explained by variation of cell surface processing since approx. 30% of each isoform was expressed on the cell surface. pHi was clamped at a range of values from 6.0-9.0 to examine regulation of AE proteins by pHi. Whereas AE2 was steeply inhibited by acid pHi, AE1, AE3 and AE3c were essentially insensitive to changes of pHi. We conclude that AE3 and AE3c can contribute to pHi recovery after cellular-acid loading.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.