Biology 3316A/B Lecture Notes - Lecture 16: Porphyromonas Gingivalis, Gamma Secretase, Anoikis

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byzantiumbat669

13 Dec 2021

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Western University

Department

Biology

Course

Biology 3316A/B

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Lecture 16 notch, alzheimer"s disease, secretase activation. Porphyromonas gingivalis in ad: gingipains are extracellular proteases that, help evade host immune response, deregulate signalling pathways, triggers tissue destruction, cleaves tau (forms nets associated with ad) Specialized apoptosis of anchored cells: gingipain k (kgp-lysine specific) and gingipain r (rgp-arginine specific) The gamma secretase clips off and cleaves ab (1-42: we don"t know if this is killing some of the drugs that get rid of the plaque. Same plaque in gingivitis is the same one that is released in the brains of alzheimer"s disease. Gingapains are extracellular proteases: k version - lysine speicific, arginine specific. Once they"re freed up, they destroy immunity, induce anoikis: can turn around and cause cells to change their fate (anokis, trigger tissue destruction, cleave tau. The bacteria may live in a nueron and get transferred to another nueron. The evidence points to amyloid beta. protein to be the major component of the plaques outside the neurons.

Related Questions

Trypsin, another member of the serine protease family has different substrate specificity, yet the same catalytic mechanism; it cleaves peptide bonds on the C side of arginine and lysine residues. What structural differences in the trypsin molecule bring about the changed substrate specificity?

QUESTION 1

Which of the following is an example of an extracellular signal molecule?

	a.	IP₃
	b.	cAMP
	c.	Insulin
	d.	Diacylglycerol

2 points

QUESTION 2

Nuclear hormone receptors _____

	a.	Bind to water soluble ligands
	b.	Activate second messengers
	c.	Regulate transcription in response to ligand binding
	d.	Are normally located on the plasma membrane

2 points

QUESTION 3

Which of the following does not occur when a receptor tyrosine kinase is bound by ligand?

	a.	Phosphorylation of the RTK
	b.	Cytoplasmic proteins bind the phosphorylated RTK
	c.	Dimerization of the RTK
	d.	The RTK binds to DNA to regulate transcription

2 points

QUESTION 4

Which of these is a logical signal-transduction pathway?

	a.	An intracellular receptor activates phospholipase C, which cleaves a membrane protein to form IP₃, which then activates the opening of an ER channel protein, which releases cyclic AMP into the cytoplasm, where it binds to an intracellular enzyme that carries out a response.
	b.	A G-protein-linked receptor activates G protein, which activates phospholipase C, which cleaves a membrane lipid to form IP₃, which binds to a calcium channel on the ER, which opens to release calcium ions into the cytoplasm, which bind to an intracellular enzyme that carries out a response.
	c.	An ion-channel receptor opens, allowing a steroid hormone to enter the cell; the steroid hormone then activates protein kinases that convert GTP to GDP, which binds to an intracellular enzyme that carries out a response.
	d.	A tyrosine-kinase receptor activates adenylyl cyclase, which activates phospholipase C, which converts ATP into cyclic AMP, which binds to an intracellular enzyme that carries out a response.

2 points

QUESTION 5

Which of the following is an example of signal amplification?

	a.	activation of an enzyme molecule
	b.	activation of a specific gene by a growth factor
	c.	Breakdown of many cAMP molecules
	d.	activation of 100 molecules by a single signal binding event

2 points

QUESTION 6

Consider a signal transduction pathway that utilizes cAMP as a second messenger to activate PKA (Protein Kinase A). Which of the following situations will result in the cellular response?

		The G protein releases GDP and binds to GTP
		The target protein (adenylyl cyclase) is inactive
		The regulatory subunits of PKA (Protein Kinase A) are bound to the catalytic subunits
		The appropriate G protein is bound to GDP

2 points

QUESTION 7

Which of the following is found in only some signal transduction pathways? [In other words, which is not found in all signal transduction pathways?]

		Receptor protein
		Extracellular signal molecule
		Intracellular signaling molecule
		Cellular response
		Effector protein

2 points

QUESTION 8

The enzyme that specifically catalyzes the conversion of ATP to cAMP is:

		Adenylyl phosphatase
		Adenylyl kinase
		Adenylyl dehydrogenase
		Adenylyl cyclase

2 points

QUESTION 9

If an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system?

		It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would employ a transduction pathway directly from an external messenger.
		It would be able to carry out reception and transduction but would not be able to respond to a signal.

2 points

QUESTION 10

A hormone signal is sent from the brain to other parts of the body via the bloodstream. Why do only certain cells respond to this signal?

		Hormones do not last long enough in the bloodstream to stimulate a cellular response
		Only cells that have a specific transcription factor gene will be able to respond to the signal
		Only cells in the immediate vicinity of the cell sending the signal will respond
		Only cells that have a receptor for the specific signal will be able to respond to it

cerisehedgehog846

a.) Amid their improvement and so as to play out their differentcapacities proficiently, cells of the immune system must discovertheir way to the right piece of the body.Depict how they do this,and give three specific examples of these signals and the cellsthat react to them. How do immune cells respond explicitly to thesesignals, or can any immune cell perceive any signal?

b.) Think about the 5 classes of pathogens. Give one example ofa pathogen from every one of these 5 classes and quickly depict thediseases it causes. List whether every one of your examples is anintracellular or extracellular pathogen, and all things considered,what kind of immune response would be most effective to clearit. Clarify why.

Consider the 5 classes of pathogens. Give one example of apathogen from each of these 5 classes and briefly describe thedisease it causes. List whether each of your examples is anintracellular or extracellular pathogen, and as such, what kind ofimmune response would be most effective to clear it. Explainwhy.

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Biology 3316A/B Lecture Notes - Lecture 16: Porphyromonas Gingivalis, Gamma Secretase, Anoikis

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