Transporters Flashcards
Function, Nephron segment, which membrane?
Na-K ATPase
Function: drives everything; keeps Na concentration low inside the cell
Nephron segment: all
Membrane: basolateral
Function, Nephron segment, which membrane?
H-K ATPase
In basolateral membrane of B-IC cells of late DT and CCD: reabsorbs H and secretes K. K will leak out apical membrane via K-channels
In apical membrane of A-IC cells of late DT and CCD: reabsorbs K and secretes H. K will leak out basolateral membrane via K-channels
Function, Nephron segment, which membrane?
H-ATPase
In basolateral membrane of beta-IC cells of late DT and CCD: Reabsorbs H made by H2CO3. The resultant HCO3- is secreted into tubule via Cl-HCO3 antiporter on apical membrane.
In apical membrane of alpha-IC cells of late DT and CCD: Secretes H made by H2CO3. The resultant HCO3 is reabsorbed into blood via Cl-HCO3 antiporter on basolateral membrane.
Function, Nephron segment, which membrane?
Ca-ATPase
Function: reabsorbs Ca into blood
Nephron segment: PT
Membrane: basolateral
Function, Nephron segment, which membrane?
ENaC
Function: epithelial sodium channels. Aldosterone sensitive
Nephron segment: late DT and CCD
Membrane: apical
Function, Nephron segment, which membrane?
Aquaporins
Function: water channels, goverened by starling forces and upregulated by ADH
Nephron segment: PT, thin descending LOH, late DT/CCD
Membrane: varies on subtype (type 2 on apical)
Function, Nephron segment, which membrane?
TRPV5
Function: Active reabsorption of Ca++
Nephron segment: DT
Membrane: apical
Function, Nephron segment, which membrane?
TRPM6
Function: Mg+ selective channel, depends on NaCl reabsorption via NCC and Na/K-ATPase. But most Mg reabsorption is paracellular
Nephron segment: Early DT
Membrane: Apical
Function, Nephron segment, which membrane?
SGLT
Function: Symporter that croses Na and glucose into the cell for reabsorption
Nephron segment: Early PT
Membrane: Apical
Function, Nephron segment, which membrane?
GLUT
Function: Transports glucose out of cell into blood
Nephron segment: Early PT
Membrane: Basolateral
Function, Nephron segment, which membrane?
Na-H Antiporters
Function: Trades Na for reabsorption and secretes an H
Nephron segment: Early and late PT
Membrane: apical
Function, Nephron segment, which membrane?
Na-K-2Cl co-transporter
Function: Primary mode of reabsorption in TAL
Nephron segment: TAL
Membrane: Apical
Function, Nephron segment, which membrane?
NaCl cotransporter
Function: primary mode of Na reabsorption in late PT; coupled to function of Na-H and Cl-base antiporters. NCC - primary mode of Na reabsorption in early DT
Nephron segment: Early and late PT
Membrane: Apical
Function, Nephron segment, which membrane?
Na-HCO3 co-transporter
Function: Biggest Na-buddy at this region. Reabsorbs both Na and HCO3
Nephron segment: Early PT
Membrane: apical
Function, Nephron segment, which membrane?
Cl-HCO3 antiporter
In apical membrane of beta-IC cells of late DT and CCD; secretes HCO3 made by H2CO3
In basolateral membrane of alpha-IC cells of late DT and CCD; reabsorbs HCO3 made by H2CO3