BIOL 200 Lecture Notes - Lecture 3: Methylation, Acetyl Group, Nuclear Pore

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copperswan658

10 Dec 2017

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Nuclear localization signal primary amino acid sequence part of the protein that needs to get into the nucleus. Receptor protein recognizes signal sequence and binds. It could be necessary but may not be sufficient. Given a living cell containing all components required for nuclear import, the only difference between a nuclear-imported protein and a cytosolic protein is the presence of an nls in near its n terminus in the primary sequence. Necessary: needed in order to get into nucleus. Sufficient: in the event that all other components are there, nls is enough to get into nucleus. Evidence: p(cid:396)otei(cid:374) (cid:449)ith (cid:373)utated nl does(cid:374)"t go i(cid:374)to (cid:374)u(cid:272)leus a(cid:374)d nl i(cid:374)se(cid:396)ted i(cid:374)to a different protein allows entry into nucleus. Purpose of the control: to have something to compare to so you that can tell that the change in the result is caused by the variable.

Related Questions

There amino acid sequence of a protein of interest is put into acomputer algorithm to search for known signals sequences. The dataobtained shows a potential nuclear localization sequence (NLS) inthe middle of the protein of interest. A further experiment is doneto determine whether the protein of interest is localized to thenucleus, and the result shows that indeed it is.

Intrigued by this, another experiment is done to determinewhether the sequence thought to be NLS is actually NLS.

What are two ways that you would manipulate this amimno acidsequence to determine whether it is both necessary and sufficientfor nuclear localization of the protein of interest?

Hint: Briefly discuss two different experiments that wouldshow:

1. is your proposed NLS required for your protein to localizethe nucleus (necessary)?

2. is the only sequence required to localize your protein to thenucleus(Sufficient)?

PLEASE! HELP ! HELP! HELP!

THANKS IN ADVANCE

plumwater-buffalo78

You have isolated a new nuclear protein, whose expression level is signficantly increased in cancer. Careful sequence analysis reveals the following sequence in the N-terminus of this protein (the positions of the amino acids are indicated): Pro(1)-Pro(2)-Val (3)-Ala(4)-Arg(5)-Lys(6)-Lys(7)-Arg(8)-Lys(9)-Lys(10)-Lys(11)-Tyr(12)-Ile(13)â¨. A construct in which amino acids 1-10 are deleted does not localize to the nucleus. However, when you fuse amino acids 1-10 to GFP, GFP remains in the cytosol.

Which of the following statements best describes the conclusion that you would draw from this experiment?

a)amino acids 1-10 are necessary but not sufficient to direct the protein's import into the nucleus

b)amino acids 1-10 are necessary and sufficient to target the protein into the nucleus

c)deletion of amino acids 1-10 disrupt the import of all proteins into the nucleus

d)amino acids 1-10 are sufficient for the nuclear import of this protein

e)amino acids 1-10 are critical for nuclear import because they interact with the Ran GTPase

erinhornet739

1. The histones that form the core of the nucleosome get into the nucleus by which of the following?

a) Passive diffusion through nuclear pores

b) Selective and facilitated active transport through nuclear pores

c) Ribosomes located in the nucleus synthetize histones in the nucleus

d) Histones are made at the ER membrane and then diffuse to the nucleus

2. Membrane proteins that belong to the golgi, lysosome, or plasma membrane first pass through which organelle before reaching their final subcellular destination?

a) The golgi apparatus

b) The smooth ER

c) The nucleus

d) The ER membrane

e) The ER lumen

3. Where in the cell would a ribosomal protein be located if it has had its nuclear export signal inactivated (non-functional or non-existent).

a) The protein would be found in the ER lumen

b) The protein would remain in the nucleus

c) The protein would be secreted

d) The protein would remain in the cytoplasm

e) The protein would be in the ER membrane

4. Where would be the final destination of a protein if it contained a NLS anywhere in the protein sequence (and which is exposed to the cytoplasm after protein folding) but also contained an ER signal sequence at the carboxy terminus?

a) The ER lumen

b) The nucleus

c) The cytoplasm

d) The inner nuclear membrane

e) The ER membrane

5. The sequence K-D-E-L serves as a retention/retrieval signal for ER proteins.

a) True

b) False

6. The following are true for both cell membrane proteins and secretory proteins EXCEPT?

a) Precursors of the mature proteins contain signal sequence.

b) Both types of proteins contain stop-transfer sequences

c) Both types of proteins enter the ER while being synthetized

d) Both types of proteins pas through the golgi apparatus

e) Both are carried by clatherin-coated vesicles

7. If you isolate a regulated secreted protein from a secretory/storage vesicle and inject it into the cytosol, is will?

a) Be secreted through channels in the plasma membrane

b) Be taken up into secretory vesicle and secreted

c) Remain in the cytosol until it is degraded

d) Be taken up into the rough ER and follow the secretory pathway

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BIOL 200 Lecture Notes - Lecture 3: Methylation, Acetyl Group, Nuclear Pore

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