Wk 1- introduction to cell signalling and detection techniques

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Questions and Answers

What is the primary advantage of using flow cytometry to detect changes in immune cell signalling pathways?

It replaces the need for antibody or fluorophore-based detection.

It enables spatial analysis of tissue samples.

It allows detection within a few hours using a single sample. (correct)

It analyzes genetic mutations more efficiently.

Which technique is best suited for analyzing a large number of proteins simultaneously?

Immunohistochemistry

Confocal microscopy

Sequencing instruments

Protein array (correct)

In the context of cell signalling, what role do ligands play?

They function solely as secondary messengers.

They bind to cellular membrane receptors or internal receptors. (correct)

They are involved in genetic mutation analysis.

They assist in protein-protein interactions.

What does immunohistochemistry primarily investigate?

Spatial distribution of cells within tissue. Signup and view all the answers

What is the primary focus of omics technologies in biological research?

Large-scale analysis of biological components. Signup and view all the answers

Which method provides fine-scale subcellular analysis?

Confocal microscopy Signup and view all the answers

Which statement accurately reflects the role of regulatory transcription factors in cell signalling?

They directly influence changes in gene expression. Signup and view all the answers

What is a potential consequence of dysregulation in cell signalling pathways?

Development of diseases. Signup and view all the answers

What type of communication occurs when signalling molecules bind to receptors within the same cell?

Intracellular communication Signup and view all the answers

Which of the following is NOT classified as a type of ligand that acts in cell signalling?

Enzymes Signup and view all the answers

What function does a second messenger typically perform in a cell?

It alters the activity of specific protein targets. Signup and view all the answers

What is the role of gap junctions in cell communication?

To allow direct physical contact for signal transmission. Signup and view all the answers

Which type of substances can initiate intracellular signalling pathways by binding to receptors?

Ligands Signup and view all the answers

How is the activity level of second messengers controlled within a cell?

Through homeostatic mechanisms. Signup and view all the answers

What is a primary characteristic of receptors in cellular communication?

They may form protein channels between cells. Signup and view all the answers

Which of the following components is essential for signal transduction when a receptor binds a ligand?

Signal protein Signup and view all the answers

What is the primary role of ligands in cell signalling?

To initiate a signalling event by binding to receptors Signup and view all the answers

Which component of cell signalling is responsible for amplifying the signal within the cell?

Second messengers Signup and view all the answers

How do changes in activity or localization of proteins affect cell signalling?

They initiate a signalling event by altering protein wiring Signup and view all the answers

Why is cell communication crucial for maintaining homeostasis?

It regulates the internal environment and functions of cells. Signup and view all the answers

What might be a consequence of cellular miscommunication in a biological system?

Onset and progression of diseases Signup and view all the answers

During signal transduction, what happens to a receptor protein upon receiving a signal?

It undergoes a structural change and activates second messengers. Signup and view all the answers

In the context of immune cell signalling, what role do transcription factors play?

They initiate and regulate gene expression related to immune responses. Signup and view all the answers

What is the function of scaffolds within a cell signalling pathway?

To organize and stabilize complexes of signalling proteins Signup and view all the answers

What are the two primary modes of cellular communication?

Intercellular communication and intracellular communication. Signup and view all the answers

Describe the role of ligands in initiating cell signaling.

Ligands bind to receptor molecules, triggering a response that can initiate intracellular signaling pathways. Signup and view all the answers

What distinguishes first messengers from second messengers in cell signaling?

First messengers are ligands that bind to receptors, while second messengers are produced in response to the binding and relay signals within the cell. Signup and view all the answers

Explain the function of gap junctions in cellular communication.

Gap junctions allow for direct physical contact and communication between adjacent cells, coordinating their activities. Signup and view all the answers

How do second messengers modify the activity of target proteins?

Second messengers bind to specific proteins, usually enzymes, altering their catalytic activities to propagate the signal. Signup and view all the answers

What factors can regulate the levels of second messengers in a cell?

Homeostatic mechanisms and various intracellular conditions regulate the production and degradation of second messengers. Signup and view all the answers

Identify two types of chemical groups that can function as ligands in cell signaling.

Hormones (such as adrenaline) and neurotransmitters (like acetylcholine) can function as ligands. Signup and view all the answers

What role does the plasma membrane play in cellular signaling?

The plasma membrane contains receptors that bind signaling molecules, facilitating communication between cells and their environment. Signup and view all the answers

What are the various triggers for cell signalling mentioned in the content?

Changes in activity or subcellular localization, metabolism, electrical charge across the membrane, and gene expression can trigger cell signalling. Signup and view all the answers

How does the conformational change in a receptor protein affect signal transduction?

The conformational change in a receptor protein launches a series of biochemical reactions within the cell, facilitating the signal transduction process. Signup and view all the answers

Explain the role of ligands as first messengers in cell signaling.

Ligands act as first messengers by binding to receptors on target cells, initiating the signalling process. Signup and view all the answers

What is the significance of second messengers in intracellular signalling?

Second messengers amplify the signal received from ligands and help coordinate subsequent intracellular signalling pathways. Signup and view all the answers

What cellular functions are essential and coordinated through cell signalling?

Key functions include maintaining homeostasis, regulating cell growth and division, and organizing cells into tissues. Signup and view all the answers

Discuss the potential impact of cellular miscommunication on biological systems.

Cellular miscommunication can lead to the onset and progression of diseases, impacting overall organismal health. Signup and view all the answers

Describe the components involved in cell signaling as listed in the content.

The components include ligands, receptors, second messengers, adapters, anchors, scaffolds, and transcription factors. Signup and view all the answers

How does a change in electrical charge across the plasma membrane influence cell signalling?

Changes in electrical charge can alter the excitability of neurons and trigger signalling events that affect cellular function. Signup and view all the answers

How do ligands function as first messengers in cell signalling?

Ligands act as first messengers by binding to specific receptors on the surface of target cells, triggering a signaling cascade that leads to cellular responses. Signup and view all the answers

What is the role of secondary messengers in the transduction of signals within a cell?

Secondary messengers amplify the signals received from first messengers, facilitating further biochemical reactions within the cell. Signup and view all the answers

Identify one key difference between intracellular and extracellular signal receptor systems.

Intracellular receptors bind to ligands that can cross the cell membrane, while extracellular receptors bind to ligands that remain outside the cell. Signup and view all the answers

How does dysregulation of cell signalling pathways contribute to disease development?

Dysregulation can lead to inappropriate activation or inhibition of signaling pathways, resulting in uncontrolled cell growth or impaired cellular functions. Signup and view all the answers

Discuss how the spatial distribution of cells can influence cell signalling outcomes.

The spatial arrangement of cells affects how signals are received and propagated, impacting the overall response and communication efficacy. Signup and view all the answers

Explain the significance of proteomics in understanding cell signalling pathways.

Proteomics provides insights into protein expressions and modifications, allowing researchers to comprehend the complexity and regulation of signaling networks. Signup and view all the answers

What mechanisms enable cells to undergo communication via direct contact?

Cells communicate through mechanisms such as gap junctions and membrane-bound ligands, allowing direct signaling between adjacent cells. Signup and view all the answers

How can flow cytometry be employed to analyze cell signalling pathways?

Flow cytometry allows for the detection and quantification of changes in signaling pathway activity in immune cells by using labeled antibodies against signaling molecules. Signup and view all the answers

examples of hormone induced cell responses mediated by cAMP

THYROID GLAD = TSH FAT = ADRENELINE , ACTH, GLUCAGON, TSH, LIVER =GLUCAGON BONE = PARTHORMONE Signup and view all the answers

What are the types of receptors?

intracellular receptors = inositol triophsphate G- protein linked receptors = Rhodopsin Enzyme coupled receptor = vascular endothelial growth cell surface receptors = ion challed - ligand gated/voltage gated primary messenger Signup and view all the answers

What do G proteins act as?

Molecular switches Signup and view all the answers

What are the three proteins that contain three distinct domains?

An α, β and γ subunits. Two of the three subunits are tethered onto the intracellular side of the plasma membrane through short lipid tails. Signup and view all the answers

What is the second group of transmembrane receptors?

Enzyme coupled receptors Signup and view all the answers

is it true enzyme coupled receptors themselves facilitate downstream signalling?

True Signup and view all the answers

What are Receptor Tyrosine Kinases (RTKs)?

Membrane receptors that play a crucial role in cellular communication by transmitting signals through phosphorylation Signup and view all the answers

What regulates RTK phosphorylation?

protein tyrosine phosphates - via removing phosphates and decaativing the receptor after ligand release during resting state Signup and view all the answers

Why are non-receptor tyrosine kinase receptors slightly different from receptor tyrosine kinases?

Non-receptor tyrosine kinases do not have a transmembrane domain and are not associated with membrane receptors, while receptor tyrosine kinases have extracellular domains that bind ligands. Signup and view all the answers

What is the key difference between non-receptor kinases and receptor kinases regarding ligand binding?

Non-receptor kinase activation occurs after ligand binds to the receptor but does not phosphorylate the receptor directly. Signup and view all the answers

Where is the non-receptor tyrosine kinase located?

In the cytoplasm Signup and view all the answers

Match the following extracellular proteins with their corresponding receptor tyrosine kinases (RTKs):

Epidermal Growth Factor (EGF) = Epidermal Growth Factor Receptor (EGFR) Platelet-Derived Growth Factor (PDGF) = Platelet-Derived Growth Factor Receptor (PDGFR) Insulin = Insulin Receptor Vascular Endothelial Growth Factor (VEGF) = Vascular Endothelial Growth Factor Receptor (VEGFR) Signup and view all the answers

Match the different types of cell signal transduction to their descriptions:

Autocrine signaling = Cell signals acting on the same cell that secretes them Paracrine signaling = Cell signals that affect nearby cells Endocrine signaling = Cell signals that travel through the bloodstream to distant cells Juxtacrine signaling = Cell signals that require direct contact between the signaling and target cells Signup and view all the answers

Match the following types of cellular signaling with their descriptions:

Autocrine = Signal acts on the same cell that secreted it Paracrine = Signal acts on nearby cells Endocrine = Signal is transported in the bloodstream to distant cells Juxtacrine = Signal requires direct contact between signaling and receiving cells Signup and view all the answers

What is a common outcome of a signaling cascade in cellular senescence?

Cell cycle arrest Signup and view all the answers

Cellular senescence refers to the process by which a cell permanently stops dividing but does not die.

True Signup and view all the answers

What is autophagy?

A process where cells break down and recycle their own components. Signup and view all the answers

What is the role of laboratory detection techniques in cell signaling?

To identify and quantify signaling molecules Signup and view all the answers

Match the following laboratory techniques with their use in cell signaling:

Western Blotting = Protein detection and quantification Flow Cytometry = Cell analysis and sorting Immunofluorescence = Visualization of proteins in cells ELISA = Quantitative measurement of proteins and antibodies Signup and view all the answers

What does antibody-based protein detection include? (Select all that apply)

Enzyme-linked immunosorbent assay (ELISA) Signup and view all the answers

What are the three main compartments of an antibody? (Select all that apply)

Variable region, Constant region, Hinge region Signup and view all the answers

How do antibody-based protein detection methods work?

They work by using antibodies that specifically bind to target proteins, allowing for identification and quantification. Signup and view all the answers

Antibody based protein detection what are the primary antibodies?

detect specific specific proteins Signup and view all the answers

Antibody-based protein detection - monoclonal antibodies are produced from what?

a single clone of B cells Signup and view all the answers

What are polyclonal antibodies produced from?

Different B cell lineages Signup and view all the answers

What are secondary antibodies used for?

To bind and detect primary antibodies in immunological assays. Signup and view all the answers

What is the primary technique used for antibody-based protein detection in Western blotting?

Electrophoresis Signup and view all the answers

What is the primary purpose of the ELISA (Enzyme-Linked Immunosorbent Assay)?

To detect and quantify proteins Signup and view all the answers

what are they what do they entail as ELISA test?

ELISA tests work by using antibodies to detect specific antigens in a sample.Micro plate-based assay utilising capture antibody specific for protein of interest (POI) POI either purified or in a complex heterogenous sample such as in cell lysate or biological fluid/extract is bound to antibody coated plate A detection antibody, specific for that interaction or phosphorylation site is added Fluorimetric or colorimetric readout Intensity of the resulting signal is directly proportional to the POI in the original sample. We can obtain quantifiable results by utilizing a calibrated standard High specificity due to the use of 2 antibodies specific for the POI in the sandwich format High sensitivity for small sample volumes and detection of low abundant proteins Signup and view all the answers

What type of assay does flow cytometry use?

Fluorescent staining Signup and view all the answers

How do flow cytometry assays work?

They analyze the physical and chemical characteristics of particles in a fluid as it passes through a laser. Signup and view all the answers

What are protein arrays?

High-throughput methods for studying protein interactions and functions Signup and view all the answers

Study Notes

Modes of Cellular Communication

Intercellular communication occurs between cells, while intracellular communication happens within a cell.
Plasma membrane-bound signaling molecules (receptors) facilitate direct cell-to-cell communication.
Receptors can either be located inside target cells or form protein channels known as gap junctions for coordination among adjacent cells.

Ligands and First Messengers

Ligands are chemical groups that bind to and affect receptor molecules, found both intracellularly and extracellularly, activated by environmental demands.
Types of signaling ligands include:
- Hormones (e.g., Adrenaline)
- Cytokines (e.g., IL-6)
- Growth Factors (e.g., Endothelial growth factor)
- Neurotransmitters (e.g., Acetylcholine, serotonin)
- ATP (Adenosine triphosphate)

Second Messengers

Second messengers modify activity of specific protein targets, usually enzymes, relaying downstream signals.
Their production is a response to extracellular and intracellular stimuli and is adjusted through homeostatic mechanisms to ensure precise signaling.

Importance of Cell Communication

Cells communicate to maintain homeostasis, regulate growth and division, organize into tissues, and coordinate functions.
Miscommunication at the cellular level can lead to diseases.

Triggers for Cell Signaling

Changes in activity or protein localization can initiate signaling events.
Factors influencing cell signaling include:
- Alterations in cellular metabolism
- Variations in electrical charge across the plasma membrane
- Modifications in gene expression
Components crucial for signaling include ligands, receptors, second messengers, adapters, anchors, scaffolds, and transcription factors.

Concept of Signal Transduction

A receptor protein binds a signal, undergoes a conformational change, and initiates biochemical reactions.
Receptor activation can lead to second messenger synthesis, coordinating intracellular signaling pathways.
Detection of changes in signaling pathways can occur rapidly through flow cytometry using specific labeling.

Detection Techniques

Antibody-based detection (protein arrays) allows analysis of multiple proteins and their modifications simultaneously.
Immunohistochemistry and tissue-based immunofluorescence are used to explore the spatial distribution of cells.
Fluorescent and confocal microscopy provide fine-scale subcellular analysis.
Genetic mutations and large-scale mRNA analysis are best suited for sequencing technologies, part of omics technologies (e.g., proteomics, genomics).

Summary

Cells utilize ligands for signaling, interacting with receptors to transduce signals via secondary messengers, affecting gene expression.
Laboratory techniques enable the exploration of signaling pathways, essential for maintaining cellular homeostasis.
Dysregulation of signaling pathways can lead to various diseases.