Proximal Tubule Gene Knockout Models

Question 1

Apical proximal tubule membrane channel

Answer 1

SGLT1 & SGLT2
NaPi II
NHE3

Question 2

What does SGLT1 and SGLT2 transport?

Answer 2

Transports Na+ and glucose into cell on apical side once both are bound

Question 3

What does NaPi II transport?

Answer 3

Na+ and phosphate ions in on apical side of proximal tubule

Question 4

What do NaPi II knockout mice show?

Answer 4

The mutants have lower serum phosphate but the older knockout mice are able to compensate for the fact that they are struggling to reabsorb phosphate so up regulate other things

Question 5

Symptoms of NaPi II knockout mice

Answer 5

• Low phosphate
• Abnormal skeletal development
• Bones are less dense

Question 6

How many transmembrane domains do SGLT1 and SNGLT2 have?

Answer 6

14

Question 7

Are SGLT1 and SGLT2 polymers or monomer?

Answer 7

Monomers

Question 8

What is familial renal glycosuria?

Answer 8

Increase [glucose] in urine

Question 9

What does NHE3 transport?

Answer 9

Uses driving force of Na+ influx to bring in Na+ and take out H+

Question 10

What do NHE3 knockout mice show?

Answer 10

Lower plasma [HCO3-], pH and BP