Lecture Set 8 Flashcards

1
Q

What are the three ways proteins interact with membranes?

A

1) Integral –> hydrophobic core regions
2) Peripheral –> non-covalently bound to membrane lipid
3) Lipid-anchored –> covalently bonded to membrane lipids

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2
Q

What is the difference between integral/peripheral

A

functionally: integral can only be removed through detergents
peripheral can be removed by chelation of Ca2+, addition of urea, change in pH or ionic strength

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3
Q

What are the four modifications of lipid anchored proteins?

A

1) palmitation
2) Meristylation
3) prenylation
4) GPI –> glycosylphosphatidylinositol
palmitation and meristylation = acetylation
first three only occur on cytosolic face

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4
Q

What are the 4 different types of integral membrane proteins?

A

type 1 = N-terminal on exoplasmic face
type 2 = C-terminal on exoplasmic face
type 3 = multi-pass protein
type 4 = multiple single pass proteins

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5
Q

what does the transmembrane sequence look like?

A

alpha-helix, hydrophobic, can be a beta-barrel

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6
Q

How can you test for protein motility in the membrane?

A

fluoresence tagging, then combine with a hybrid cell through virus-induced fusion, then watch mixture of fluorescent proteins

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7
Q

where are oligosaccaride chains found on proteins?

A

noncytosolic side

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8
Q

How can cell surface protein movement be restricted?

A

1) attachment to extracellular matrix
2) attach to cell cortex
3) interact with proteins on other cells
4) junctional barriers (ex. tight junctions)

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