Nature 473, 337 (2011) WS 2023/4 - Lecture 5 Cellular Programs

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What is the basis for classifying the cell cycle state in the given experiment?

Phosphorylation events

Microtubule polymerization

DNA content (correct)

Protein abundance

Why is Nocodazole block considered efficient in synchronizing cells?

It alters protein abundance

It interferes with microtubule polymerization (correct)

It affects phosphorylation events

It enhances DNA content

What was the threshold used for subsequent analysis in the experiment?

4-fold change in protein abundance (correct)

5-fold change in microtubule polymerization

3-fold change in phosphorylation events

2-fold change in protein abundance

How was protein abundance monitored in Experiment 1?

Using mass spectrometry (D) Signup and view all the answers

Which technique was used to obtain information from the 6 stages of the cell cycle?

SILAC peptide triplet (C) Signup and view all the answers

What was the purpose of quantifying cell cycle markers in different cell populations?

To understand changes in protein abundance throughout the cell cycle (B) Signup and view all the answers

What is the purpose of SILAC labeling in the context of the study mentioned?

To quantify protein expression levels across different stages of the cell cycle. (D) Signup and view all the answers

Which statement accurately explains the difference between the high-turnover and low-turnover proteins in terms of H/L ratios?

The H-concentration of high-turnover protein increases over time. (D) Signup and view all the answers

In the context of the study, what was the role of thymidine in HeLa cell synchronization?

Blocking cells from entering the S phase of the cell cycle. (A) Signup and view all the answers

Why were 3 different isotopic forms of arginine and lysine used for SILAC labeling in HeLa cells?

To allow differentiation between 3 distinct cell populations. (D) Signup and view all the answers

Which technique was used to quantify protein expression levels in the study discussed?

Mass Spectrometry (A) Signup and view all the answers

What was the role of nocodazole in the study involving HeLa cells?

To block entry into a specific phase of the cell cycle. (C) Signup and view all the answers

What is the significance of low occupancy phosphorylation of a protein?

It indicates that only a fraction of the protein copies are phosphorylated at any given time. (B) Signup and view all the answers

What technique was used to analyze all proteins modified by phosphorylation during different stages of the cell cycle in human HeLa cells?

Mass spectrometry (D) Signup and view all the answers

What does SILAC stand for in the context of protein quantification?

Stable Isotope Labeling by Amino Acids in Cell Culture (B) Signup and view all the answers

What happens when non-labelled cells are transferred to heavy SILAC growth medium during protein turnover quantification?

Newly synthesized proteins remain in light form and preexisting proteins incorporate heavy label. (D) Signup and view all the answers

How many phosphorylated proteins were identified during the analysis of the phospho-proteome in human HeLa cells?

6695 (D) Signup and view all the answers

What proportion of all proteins was found to be phosphorylated based on the findings presented?

~70% (B) Signup and view all the answers