AbuArish_CPPS325_March10_2025_Lecture 2_upload (1)

Question 1

What is the concept of fluorescence?

Answer 1

The concept of fluorescence involves the emission of light by a substance that has absorbed light or other electromagnetic radiation.

Question 2

What is the Jablonski Diagram?

Answer 2

The Jablonski Diagram is a graphical representation of the electronic states of a molecule and the transitions between them, illustrating processes like fluorescence.

Question 3

Define a fluorescent molecule.

Answer 3

A fluorescent molecule is a compound that can absorb light at a certain wavelength and then emit light at a longer wavelength.

Question 4

What is fluorescence confocal microscopy?

Answer 4

Fluorescence confocal microscopy is a technique that increases optical resolution and contrast by using a spatial pinhole to block out-of-focus light.

Question 5

What is the resolution limit in fluorescence microscopy?

Answer 5

The resolution limit in fluorescence microscopy refers to the smallest distance between two points that can be distinguished as separate entities.

Question 6

What does fluorescence super-resolution microscopy include?

Answer 6

Fluorescence super-resolution microscopy includes techniques such as STED (Stimulated Emission Depletion) microscopy.

Question 7

What is Image Correlation Spectroscopy (ICS)?

Answer 7

Image Correlation Spectroscopy (ICS) is a technique used to quantify the behaviors of proteins in live cells by analyzing the correlation of fluorescent signals over time.

Question 8

Why do we study protein behaviors in cells?

Answer 8

We study protein behaviors in cells to best understand protein function in health and disease, focusing on molecular behaviors.

Question 9

What is CFTR?

Answer 9

CFTR stands for Cystic Fibrosis Transmembrane Conductance Regulator, which functions as an ion channel.

Question 10

What is the significance of CFTR localization?

Answer 10

CFTR localization at the plasma membrane is essential for its function as an ion channel, and its loss is associated with cystic fibrosis.

Question 11

What is the effect of cholesterol and ceramide lipids on CFTR?

Answer 11

Cholesterol and ceramide lipids modulate CFTR distribution and stability at the plasma membrane of bronchial epithelial cells.

Question 12

What happens to CFTR concentration in cystic fibrosis?

Answer 12

In cystic fibrosis, only 5% of mutant CFTR (ΔF508-CFTR) is trafficked to the plasma membrane, reducing its concentration and function.

Question 13

What is the impact of CFTR dysfunction?

Answer 13

CFTR dysfunction leads to diminished ion conductance and disrupted water secretion, resulting in thickened mucus and impaired mucociliary clearance.

Question 14

What changes occur in CFTR distribution after stimulation?

Answer 14

Stimulation of CFTR function causes small clusters to coalesce into large platforms, indicating a change in distribution associated with altered function.

Question 15

What are the two mobility states of CFTR observed in live cell imaging?

Answer 15

The two mobility states of CFTR are fast diffusive mobility and slow diffusive mobility, with the latter occurring when proteins are confined inside microdomains.

Question 16

What is the role of airway surface liquid (ASL)?

Answer 16

Airway surface liquid (ASL) is important for mucus hydration and mucociliary clearance, which helps maintain airway health.

Question 17

What is the definition of a diffusion coefficient (D)?

Answer 17

The diffusion coefficient (D) is defined as the area covered by particles divided by time.

Question 18

What is the relationship between CFTR and cholesterol?

Answer 18

CFTR and cholesterol colocalize at the plasma membrane, suggesting that CFTR clustering is modulated by cholesterol.

Question 19

True or False: CFTR is primarily localized in the nucleus.

Answer 19

False

Question 20

Fill in the blank: The main function of CFTR is to conduct _______.

Answer 20

Cl- and HCO3-

Question 21

What are the consequences of CFTR dysfunction in cystic fibrosis?

Answer 21

Consequences include acidic airway surface liquid, thickened mucus, impaired mucociliary clearance, and increased risk of bacterial infections.

Question 22

What are lipid rafts?

Answer 22

Lipid rafts are microdomains within the plasma membrane that are enriched in cholesterol and sphingomyelin, playing roles in protein localization and signaling.

Question 23

How are protein interactions with other proteins characterized?

Answer 23

Protein interactions can be characterized by their localization, distribution, and mobility in different cellular environments.

Question 24

What are lipid rafts enriched in?

Answer 24

Cholesterol and sphingomyelin

Lipid rafts are specialized membrane domains that play a crucial role in cellular signaling and protein distribution.

Question 25

What is the effect of cholesterol oxidation on CFTR?

Answer 25

Reduces CFTR confinement and clustering ## Footnote CFTR stands for Cystic Fibrosis Transmembrane Conductance Regulator, a protein that regulates ion transport across epithelial membranes.

Question 26

What happens to CFTR cluster size with increased membrane cholesterol?

Answer 26

Increases CFTR cluster size ## Footnote Cholesterol esterification by CEase contributes to maintaining lipid raft integrity.

Question 27

How does CFTR clustering relate to membrane stability?

Answer 27

Increases stability at the plasma membrane by reducing internalization ## Footnote CFTR clustering inside lipid rafts influences its functional stability.

Question 28

What role does ceramide play in CFTR membrane distribution?

Answer 28

Modulates CFTR membrane distribution ## Footnote Ceramide-rich platforms are crucial for CFTR aggregation and function.

Question 29

What is the impact of thapsigargin on CFTR?

Answer 29

Acts as a cell stressor ## Footnote Thapsigargin is known to induce endoplasmic reticulum stress.

Question 30

What is the relationship between reactive oxygen species (ROS) and ASMase?

Answer 30

VIP leads to ROS generation, activating ASMase ## Footnote ASMase is an enzyme that generates ceramide from sphingomyelin.

Question 31

What is the function of methyl-β-cyclodextrin (MβCD)?

Answer 31

Extracts cholesterol from the membrane and disrupts lipid rafts ## Footnote MβCD is commonly used in experiments to study lipid raft dynamics.

Question 32

What are the two populations of CFTR observed in confocal images?

Answer 32

Diffuse and clusters ## Footnote These populations indicate different states of CFTR aggregation and membrane localization.

Question 33

Fill in the blank: CFTR clustering is modulated by _______.

Answer 33

cholesterol

Question 34

True or False: Intact lipid rafts are essential for platform formation.

Answer 34

True ## Footnote The integrity of lipid rafts is necessary for proper protein localization and function.

Question 35

What do ceramide-rich platforms increase in terms of CFTR?

Answer 35

Recruitment and tethering at the plasma membrane ## Footnote This leads to enhanced expression and stability of CFTR.

Question 36

What type of analysis is ideal for measuring CFTR molecular behaviors at the plasma membrane?

Answer 36

ICS analysis ## Footnote ICS stands for Imaging Correlation Spectroscopy, which provides insights into protein dynamics.

Question 37

What happens to sphingomyelin when ASMase is activated?

Answer 37

It is hydrolyzed into ceramide ## Footnote This process is essential for the formation of ceramide-rich platforms.

Question 38

What is the primary focus of Abu-Arish et al.'s 2019 study?

Answer 38

The modulation of CFTR membrane distribution by ceramide ## Footnote This study emphasizes the role of lipids in protein localization.

Question 39

What does the term 'coalescence' refer to in the context of lipid rafts?

Answer 39

The merging of lipid raft components to form larger platforms ## Footnote Coalescence is important for the stability and function of membrane proteins.