Transporters

Question 1

What are ABC transporters?

Answer 1

ATP-binding cassette
primary active
generally efflux

Question 2

List the ABC transporters

Answer 2

MDR (MultiDrug Resistance)
MRP (Multidrug Resistance associated Proteins)
BCRP (Breast Cancer Resistance Proteins)

Question 3

MDR1 (P-gp) is expressed in:

Answer 3

most tissues

transport in normal cells of: intestine, liver, kidney, BBB, placenta (protects fetus from xenobiotics), tumor cells

Question 4

MDR1 substrates

Answer 4

loperamide, digoxin, fexofenadine, paclitaxel

generally lipophilic > passive diffusion

Question 5

MRP1 is expressed in:

Answer 5

ubiquitous (kidney, BBB)

Question 6

MRP1 & 2 substrates

Answer 6

vincristine, methotrexate, saquinavir, GSH, oxidized glutathione

Question 7

MRP2 & 3 are expressed in:

Answer 7

liver, kidney, intestine

Question 8

MRP3 substrates

Answer 8

etoposide, methotrexate, glycocholate, taurocholate

Question 9

MRP4 & 5 are expressed in:

Answer 9

ubiquitous

Question 10

MRP4 substrates

Answer 10

6-mercaptopurine, furosemide, adefovir, cefazolin

Question 11

MRP5 substrates

Answer 11

6-mercaptopurine, adefovir

Question 12

MRP6 is expressed in:

Answer 12

liver, kidney

Question 13

MRP6 substrates

Answer 13

doxorubicin, etoposide

Question 14

BCRP is expressed in:

Answer 14

tumor cells (over expression)
placenta (high expression)
intestine, liver, kidney, brain, heart, ovaries

Question 15

BCRP substrates

Answer 15

topotecan, mitozantrone, doxorubicin, daunorubicin, heme and other porphyrins

Question 16

What are SLC transporters?

Answer 16

solute carrier
secondary active
generally influx

Question 17

List the SLC transporters

Answer 17

OATP (Organic Anion Transporting Polypeptides)
OAT( Organic Anion Transporters)
OCT (Organic Cation Transporters)
MCT (MonoCarboxylate Transporters)
PEPT (PEPtide Transporters)
NT (Nucleoside Transporters)

Question 18

OATP is expressed in:

Answer 18

OATP1B1 (SCLO1B1): sinusoidal membrane of the liver

Question 19

OATP substrates

Answer 19

statins, bilirubin, estrogen conjugates

Question 20

OAT is expressed in:

Answer 20

kidney

Question 21

OAT substrates

Answer 21

OAT1:
acyclovir, penicillins, methotrexate

OAT3:
furosemide, penicillins, pravastatin, methotrexate

Question 22

OCT is expressed in:

Answer 22

OCT1: liver

OCT 2: kidney

Question 23

OCT substrates

Answer 23

OCT1:
metformin, lamivudine, oxaliplatin

OCT2:
metformin, lamivudine, oxaliplatin, procainamide, cisplatin

Question 24

MCT is expressed in:

Answer 24

ubiquitous

Question 25

MCT substrates

Answer 25

(driven by proton gradient)

lactate, pyruvate, mevalonic acid, gabapentin enacarbil (prodrug), pravastatin

Question 26

PEPT is expressed in:

Answer 26

PEPT1: intestine, kidney

PEPT2: kidney

Question 27

PEPT substrates

Answer 27

ACE inhibitors (captopril, enalapril), B-lactam antibiotics (caphalexin), prodrugs (valacyclovir)

(have amide bonds that mimic bonds in peptides

Question 28

NT is expressed in:

Answer 28

widespread

Question 29

NT substrates

Answer 29

nucleosides (sugar+base)

cytarabine, gemcitabine, fludarabine, ribavirine

CNTs & ENTs work together