Here, we show the following in the apical membrane of the S1 segment of the proximal tubule.

• The NaPi-IIa cotransporter, which brings 3 sodium ions with 1 HPO4^2-
• The NaPi-IIc cotransporter, which brings 2 sodium ions with 1 HPO4^2- (not in S3 segment)
• The PiT-2 cotransporter, which brings 2 sodium ions with 1 H2PO4^-

The basolateral transporter of phosphate forms into the interstitial space is still unknown.

The same electrochemical gradient generated by the Na/K ATPase mentioned in the previous post serves as the force behind the sodium/phosphate cotransporter

Bibliography

Biber,J, N. Hernando, I. Forster, H. Murer . “Regulation of Phosphate Transport in Proximal Tubules." European Journal of Physiology 408, No. 1 (2009): 39-52. https://doi.org/10.1007/s00424-008-0580-8.

Previous Posts in this Series

Renal Tubular Transport #1. S1 Segment, Proximal Tubule. Sodium Transport 1 (Sodium/Hydrogen Ion Transport) (2nd Edition)

Renal Tubular Transport #2. S1 Segment, Proximal Tubule. Sodium Transport 2 (Sodium/Phosphate Transport) (2nd Edition)

Renal Tubular Transport #3. S1 Segment, Proximal Tubule. Sodium Transport 3

Renal Tubular Transport #4. S1 Segment, Proximal Tubule. Sodium Transport 4

Renal Tubular Transport #5. S1 Segment, Proximal Tubule. Sodium Transport 5

Renal Tubular Transport #6. S1 Segment, Proximal Tubule. Sodium Transport 6

Renal Tubular Transport #7. S1 Segment, Proximal Tubule. Sodium Transport 7

Renal Tubular Transport #8. S1 Segment, Proximal Tubule. Sodium Transport 8

Renal Tubular Transport #9. S1 Segment, Proximal Tubule. Potassium Transport 1

Renal Tubular Transport #10. S1 Segment, Proximal Tubule. Potassium Transport 2

Renal Tubular Transport #11. S1 Segment, Proximal Tubule. Calcium Transport 1

Renal Tubular Transport #12. S1 Segment, Proximal Tubule. Water Transport 1

Renal Tubular Transport #13. S1 Segment, Proximal Tubule. Magnesium Transport 1

Renal Tubular Transport #14. S1 Segment, Proximal Tubule. Glucose Transport 1