ANAT 212 Lecture Notes - Lecture 10: Oligosaccharyltransferase, Copii, Clathrin

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amaranthtiger876

30 Mar 2020

School

McGill University

Department

Anatomy & Cell Biology

Course

ANAT 212

Professor

Jason Young

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Document Summary

Last lecture: cop-ii (go forward from er to golgi), cop-i (go backward from golgi to er) and clathrin coated vesicles, from the golgi to the plasma membrane and to the endosomes and from the plasma membrane to the endosomes. Compare and contrast: there are 3 different types of vesicles coats. These are protein coats which form cages and shapes the vesicles. Initiation: initiator sar1 (cop-ii), arf (cop-i) and pi-phosphate (ccv) Signals on cargo: er exit signals for copii, er retrieval signals for copi, mono-ubiquitin can serve as a signal for endocytosis for ccv. For cop-ii and cop-i, the protein coat itself is enough to pinch them off. Ccv, there is a protein called dynamin which is a gtpase that forms spirals around the neck, hydrolyze. Gtp and squeeze the neck and pinch it off. Different mechanisms for cop-ii and cop-i which works in parallel (hydrolyzes of.

Related Questions

The vesicles that transport materials from donor membranes to acceptor membranes include:

	1.	COP-II coated vesicles
	2.	COP-III coated vesicles
	3.	COP-I coated vesicles
	4.	Clathrin coated vesicles

2.5 points

QUESTION 11

During skeletal muscle contraction, the roles of ATP include:

	1.	ATP is not required for forming the crossbridges between myosin and actin filaments.
	2.	ATP is utilized as a structural linker to mediate the interaction between myosin and actin filaments
	3.	Hydrolysis of ATP provides energy for myosin head to move along actin filaments and the binding of ATP to myosin head allows the detachment of myosin fromactin filaments.
	4.	ATP binds to actin filaments to drive the power stroke of myosin head.

2.5 points

QUESTION 12

One of the functions of smooth endoplasmic reticulum is

	1.	Synthesizing steroid hormone in the endocrine cells of the gonad and adrenal cortex
	2.	Serves as the starting point of the biosynthetic pathway
	3.	Synthesizing secretory proteins
	4.	Degrading cell debris

2.5 points

QUESTION 13

The function of COP-II coated vesicles is mainly:

	1.	Transporting materials from endosomes to Golgi complex
	2.	Moving materials from the ER to the ERGIC and Golgi complex.
	3.	Transporting materials from Golgi complex back to endoplasmic reticulum.
	4.	Involved in receptor-mediated endocytosis.

2.5 points

QUESTION 14

Which of the following processes is completed in rough endoplasmic reticulum?

	1.	Chaperones help misfolded proteins fold correctly.
	2.	Proteins that target to nucleus are synthesized in rough endoplasmic reticulum.
	3.	O-linked glycosylation occurs in rough endoplasmic reticulum.
	4.	Misfolded proteins are destructed in rough endoplamic reticulum.

2.5 points

QUESTION 15

Kinesin is the motor protein that coorporates with microtubules. It has the following functions:

	1.	It uses GTP as energy source.
	2.	It can hydrolyze ATP and use the energy to drive cargo along microtubules from minus end to plus end.
	3.	It has a globular head that can act as GTPase
	4.	The tail of kinesin is more diverse and binds to cargo

2.5 points

QUESTION 16

For correct segregation and trafficking, lysosomal proteins are tagged in the cis-Golgi with phosphorylated mannose residues, and then the tagged lysosomal enzymes are recruited to clathrin coated vesicles by mannose 6-phosphate receptors.

True

False

2.5 points

QUESTION 17

The process that specialized cells, such macrophages, engulf relatively large particles is:

	1.	Called pinocytosis
	2.	Called phagocytosis
	3.	Mediated by COP-II coated vesicles
	4.	Called autophagy

2.5 points

QUESTION 18

Proteins synthesized on rough endoplasmic reticulum and smooth endoplasmic reticulum are imported co-translationally to their destinations

True

False

2.5 points

QUESTION 19

Treatment of cells with a drug that promotes microtubule disassembly disperses Golgi complex into separate stacks of membrane compartments, suggesting that:

	1.	Golgi complex is made of microtubules.
	2.	Microtubules are important for the organization of Golgi complex.
	3.	Microtubules are transported into Golgi complex
	4.	Golgi complex is composed of tubulin proteins

2.5 points

QUESTION 20

Which of the following is correct about signal sequence of a secretory protein?

	1.	It is an âaddress codesâ for protein trafficking pathways
	2.	It is usually located at the C-terminus.
	3.	It targets the ribosome and the protein that is being synthesized to endoplasmic reticulum.
	4.	It is removed in Golgi complex.

apricotgrasshopper117

1) how does the timing and location of Arf1-GTP hydrolysis contribute the transport of COPI coated vesicles?

2) Consider cargo proteins that are destined for secretion to the extracellular space. For each of the following pairs of mutations or conditions, predict where the cargo will end up (ex. in the cytoplasm, a specific organelle, transport vesicles, multiple places, extracellular space) for: (i) & (ii) Each individual condition; & (iii) The combination of both.

A.(i) Normal Sar1 is mutated so that it hydrolyzes GTP immediately after binding GTP.

(ii)The signal recognition particle is mutated to be unable to bind to the SRP receptor.

(iii)Both

B.(i) A mitochondrial signal sequence is added to the C-terminus of the cargo protein.

(ii)v-SNAREs on COPII coated vesicles are mutated to be unable to bind t-SNAREs

(iii)Both

C. (i) COPII coat proteins are mutated so they donât bind to the ER membrane.

(ii)COPI coat proteins are mutated so they donât bind to the Golgi membrane.

(iii)Both

D.(i) Normal Sar1 is mutated so it binds tightly to GDP and cannot exchange it for GTP. (This leads to Sar1*-GDP being the only form of the protein in the cell.)

(ii) A transmembrane domain is added to the cargo protein.

(iii)Both

1) In the major biosynthetic pathway, what is the order in which mRNA moves through the various organelles?

2) Compare and contrast the structure and function of the smooth endoplasmic reticulum and the rough endoplasmic reticulum?

3) Is SAR1 COPI or COPII? What type of protein is this? What causes SAR1 to active and what protein is necessary for this to occur?
4) Dynamin binds where clathrin meets the plasma membrane. As dynamin binds, it forms a ring that is then pinched so that the vesicle can be released from the plasma membrane. What allows for this to occur?

5) What are three different mechanisms of protein translocation? Briefly describe the state of the proteins when translocated in each of these ways.

6) What is the KDEL sequence stand for and how does it function within the cell? What type of transport is it associated with?

7) In what cellular compartment would a glycoprotein be expected to have its greatest mannose content? Its greatest N-acetylglucosamine content? Its greatest sialic acid content?

8) Would you expect the properties of the cisternal side of Golgi membranes to be more similar to the extracellular or cytosolic side of the plasma membrane? Why?

9) ________ are the site of cellular digestion, in which digestion occurs with the help of 50 __________. _____ digest proteins and ____ digest lipids.

10) Name two proteins you would expect to find as integral components of the RER membrane that would be absent from the SER? Name two proteins of the SER that would not be present in the RER?

ANAT 212 Lecture Notes - Lecture 10: Oligosaccharyltransferase, Copii, Clathrin

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