Atp-dependent Efflux Transporters
Atp-dependent Efflux Transporters - Related Videos
07:47
A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters
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Cited by 5 •
2015
Proteoliposomes are used to study purified channels and transporters reconstituted in a well-defined biochemical environment. An experimental procedure to measure efflux mediated by these proteins is illustrated. The steps to prepare proteoliposomes, perform the recordings, and analyze data to quantitatively determine the functional properties of the reconstituted protein are described.
01:31
ATP Yield
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2019
Cellular respiration produces 30 - 32 ATP per glucose molecule. Although most of the ATP results from oxidative phosphorylation and the electron transport chain (ETC), 4 ATP are gained beforehand (2 from glycolysis and 2 from the citric acid cycle). The ETC is embedded in the inner mitochondrial membrane and is comprised of four main protein complexes and an ATP synthase. NADH and FADH2 pass electrons to these complexes, which pump protons into the intermembrane space. This distribution of...
08:32
The ATP Bioluminescence Assay
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2023
In fireflies, the luciferase enzyme converts a compound called luciferin into oxyluciferin, and produces light or “luminescence” as a result. This reaction requires energy derived from ATP in order to proceed, so researchers have exploited the luciferase-luciferin interaction to gauge ATP levels in cells. Given ATP’s role as the cell’s currency of energy, the ATP bioluminescence assay can provide insight into cellular metabolism and overall cell health.In this video, JoVE discusses cellular...
10:14
Biochemical Assays for Analyzing Activities of ATP-dependent Chromatin Remodeling Enzymes
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Cited by 4 •
2014
Here we describe biochemical assays that can be used to characterize ATP-dependent chromatin remodeling enzymes for their abilities to 1) catalyze ATP-dependent nucleosome sliding, 2) engage with nucleosome substrates, and 3) hydrolyze ATP in a nucleosome- or DNA-dependent manner.
01:08
Hydrolysis of ATP
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2019
The bonds of adenosine triphosphate (ATP) can be broken through the addition of water, releasing one or two phosphate groups in an exergonic process called hydrolysis. This reaction liberates the energy in the bonds for use in the cell—for instance, to synthesize proteins from amino acids. If one phosphate group is removed, a molecule of ADP—adenosine diphosphate—remains, along with inorganic phosphate. ADP can be further hydrolyzed to AMP—adenosine monophosphate—by the removal of a second...
FAQs
Their key structural elements are transmembrane domains connected to nucleotide-binding domains. The transmembrane regions form the pathway through which substrates cross the membrane, whereas the nucleotide-binding regions interact with ATP. This linked architecture allows chemical energy input at one part of the protein to produce coordinated structural changes that control substrate movement.
ATP binding and hydrolysis regulate alternating transporter conformations. Binding supplies the trigger for a structural transition, and hydrolysis supports the cycle that returns the protein toward another conformation. These coordinated changes determine when a substrate is engaged and moved across the membrane, making ATP turnover central to directional export rather than a passive diffusion process.
The site of transporter activity determines which pharmacokinetic process is affected. Efflux in the intestine can influence drug absorption, activity in tissues can alter distribution, and transport associated with renal or biliary pathways can affect clearance. Consequently, the same transporter mechanism may change circulating exposure, tissue concentrations, or elimination depending on its anatomical location.
By exporting multiple drugs from cells, these transporters can reduce intracellular drug exposure across more than one treatment. This broad substrate effect can contribute to multidrug resistance, particularly when transporter activity prevents adequate drug accumulation. In pharmacology, the resulting reduction in cellular exposure helps explain why transporter behavior can influence treatment response as well as drug disposition.
Inhibition reduces transporter activity, whereas induction increases it, so the two processes can shift drug exposure in opposite directions. Changes in efflux may alter absorption, distribution, clearance, or penetration into protected compartments. Evaluating either interaction therefore requires considering the affected transporter, the drug's disposition pathway, and the resulting change in treatment response or toxicity.
P-glycoprotein and breast cancer resistance protein can influence several stages of a drug's movement through the body. Their activity may modify intestinal absorption, tissue distribution, renal or biliary clearance, and penetration into protected compartments. These effects make transporter status relevant when interpreting pharmacokinetic differences, exposure changes, and variable drug responses.
Transporter activity can change how much drug reaches particular tissues and how long exposure persists before clearance. Reduced penetration or increased export may weaken treatment response, while altered distribution or elimination may contribute to toxicity. Pharmacology therefore considers these proteins alongside drug properties to interpret exposure, therapeutic effects, and clinically important transporter-mediated interactions.