Drug Targets: Transporters

Question 1

What are transporters?

Answer 1

Membrane proteins that form a pore within the plasma membrane to allow passage of various types of molecules

Question 2

Molecule transported is referred to as a?

Answer 2

Substrate

Question 3

Facilitative/passive transporters describe

Answer 3

No energy needed
Movement of solutes follow the concentration gradient

Question 4

Describe active transporters

Answer 4

Requires energy
Movement of solutes against the concentration gradient

Question 5

Two types of active transporters

Answer 5

Primary active and secondary active transporters

Question 6

describe driving energy source for primary vs secondary active transporters

Answer 6

Primary: energy source = ATP hydrolysis
Secondary: energy source = movement of another solute going down its concentration gradient

Question 7

Transporter can be classified how?

Answer 7

Based on their structure/function
In type of transport
Direction of transport

Question 8

Function of direction of the transport classification includes

Answer 8

Influx
Efflux
Bidirectional

Question 9

Function of type of transport is classification includes?

Answer 9

Facilitative/passive transporters
Active transporters

Question 10

Based on their structure/function classification includes?

Answer 10

SLC transporters
ABC transporters
ATPase transporters
…and others

Question 11

SLC transporters are

Answer 11

Solute carriers

Question 12

SLC transporters are mostly what transporters?

Answer 12

Facilitative/ secondary active transporters

Question 13

How does ABC transporters work?

Answer 13

Use energy of ATP to transport various substances ( primary active transporters)

Question 14

How do ATPase transporters work?

Answer 14

Use ATP hydrolysis to drive the transport of protons across a membrane

Question 15

Role of transporters

Answer 15

Transport amino acids ( for protein synthesis), glucose, vitamins etc
Transport of metals- essential cofactors for enzymes
Transport of neurotransmitters
Drag targeting transporters

Question 16

Example of transport of neurotransmitters

Answer 16

SERT- takes back serotonin (5-HT) into presynaptic neuron
SERT- target of many anti-depressive drugs

Question 17

Example of drug targeting transporters

Answer 17

Diuretics, neuropsychiatric drugs, glucose transporter inhibitors etc

Question 18

Na-K-Cl co-transporter located?

Answer 18

Found in kidney

Question 19

Loop diuretics (furosemide) are used for? And whys?

Answer 19

Used for heart failure, hypertension, pulmonary oedema
Why? Inhibition of transport- less Na+/K+ reabsorbed- kidney pass more water- diuresis ( increased urine flow)

Question 20

Explain Na-K-Cl cotransporter

Answer 20

Role in Na+ and K+ reabsorption (from the tubule lumen to the blood stream)

Question 21

Classify Na/K/Cl cotransporter based on direction of transport, type of transport, structure /function

Answer 21

Direction- influx
Type of transport-secondary active
Structure / function- SLC transporter

Question 22

Example of role of transporters in drug PK (ADME)

Answer 22

Transport drugs from intestinal lumen to bloodstream-can enhance drug absorption
Transporters can protect the intestine against ingested toxins - pump drugs out of intestines- decreased absorption

Question 23

Physiological role of p-glycoprotein (p-gp) / multidrug resistance protein 1 (MDR1)

Answer 23

Enhances elimination of toxic substances and harmful agents

Question 24

Classify P-gp/ MDR1 based on direction of transport, type of transport, structure /function

Answer 24

Direction of transport - efflux
Type of transport-primary active
Structure / function- ABC transporter

Question 25

The human breast cancer resistance protein (BCRP) is a transporter that uses ATP hydrolysis to transport broad range of substrates out of the cell. How can we classify BCRP based on type of transport?

Answer 25

Primary active transporter