SLC4A11 is an EIPA-sensitive Na(+) permeable pHi regulator.
Diego G Ogando, Supriya S Jalimarada, Wenlin Zhang, Eranga N Vithana, Joseph A Bonanno
文献索引:Am. J. Physiol. Cell Physiol. 305(7) , C716-27, (2013)
全文:HTML全文
摘要
Slc4a11, a member of the solute linked cotransporter 4 family that is comprised predominantly of bicarbonate transporters, was described as an electrogenic 2Na(+)-B(OH)4(-) (borate) cotransporter and a Na(+)-2OH(-) cotransporter. The goal of the current study was to confirm and/or clarify the function of SLC4A11. In HEK293 cells transfected with SLC4A11 we tested if SLC4A11 is a: 1) Na(+)-HCO3(-) cotransporter, 2) Na(+)-OH(-)(H(+)) transporter, and/or 3) Na(+)-B(OH)4(-) cotransporter. CO2/HCO3(-) perfusion yielded no significant differences in rate or extent of pHi changes or Na(+) flux in SLC4A11-transfected compared with control cells. Similarly, in CO2/HCO3(-), acidification on removal of Na(+) and alkalinization on Na(+) add back were not significantly different between control and transfected indicating that SLC4A11 does not have Na(+)-HCO3(-) cotransport activity. In the absence of CO2/HCO3(-), SLC4A11-transfected cells showed higher resting intracelllular Na(+) concentration ([Na(+)]i; 25 vs. 17 mM), increased NH4(+)-induced acidification and increased acid recovery rate (160%) after an NH4 pulse. Na(+) efflux and influx were faster (80%) following Na(+) removal and add back, respectively, indicative of Na(+)-OH(-)(H(+)) transport by SLC4A11. The increased alkalinization recovery was confirmed in NHE-deficient PS120 cells demonstrating that SLC4A11 is a bonafide Na(+)-OH(-)(H(+)) transporter and not an activator of NHEs. SLC4A11-mediated H(+) efflux is inhibited by 5-(N-ethyl-N-isopropyl) amiloride (EIPA; EC50: 0.1 μM). The presence of 10 mM borate did not alter dpHi/dt or ΔpH during a Na(+)-free pulse in SLC4A11-transfected cells. In summary our results show that SLC4A11 is not a bicarbonate or borate-linked transporter but has significant EIPA-sensitive Na(+)-OH(-)(H(+)) and NH4(+) permeability.
相关化合物
相关文献:
2015-04-13
[Biomacromolecules 16(4) , 1382-9, (2015)]
2014-10-01
[J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol. 184(7) , 865-76, (2014)]
2014-12-08
[Biomacromolecules 15(12) , 4561-9, (2014)]
2014-08-07
[Nanoscale 6(15) , 8720-5, (2014)]
2014-01-01
[PeerJ 2 , e284, (2014)]