Lecture 1

Question 1

Binding site for SH2 and PTB domain

Answer 1

Phosphotyrosine

Question 2

Bacteria and Archaeal vs Eukaryotic proteins

Answer 2

Bacterial Archaeal: single domain

Eukaryotic proteins: beads on a string (each bead is different domain with unique function

Question 3

7 steps in JAK/STAT signalling

Answer 3

1. ligand binding
2. dimerization and JAK phosphorylation of receptor
3. STAT binds to phosphorylation
4. JAK phosphorylate STAT
5. STAT forms dimer
6. STAT dimer travels into nucleus
7. binds to DNA and change gene expression

Question 4

What domain recognizes methylated lysine residue on histone proteins?

Answer 4

Chromodomains

Inhibition chromodomain binding by kinase phosphorylation (steric hindrance)

Question 5

Intramolecular interactions lock

Answer 5

binding of SH3 and SH2 allows kinase to adopt an on conformation

Question 6

What domain binds to acetylated lysine residue 9 and 14?

Answer 6

2 Bromo domain

trimethylated prevents bromo domain binding

Question 7

3 steps in Sic 1 (Multi site switch)

Answer 7

1. Sic1 inhibits cell into cell cycle
2. Ubiquitylation and degradation of Sic1 removes inhibition
3. Cell progress into S/M phase of cell cycle

fine tune of cell requires a not just one ubiquitin and phosphorylation

Question 8

SCF complex

Answer 8

Tetrameric E3 ligase

recognized by CDC4 and SKP2

adds ubiquitin to Sic1 cause Sic1 degradation

Question 9

Calmodulin binding

Answer 9

Absence of calcium, inactive

Release of calcium following IP3 binding to ER: interacts with calmodulin and cause it to undergo a global change in conformation to an open form (active)

Active calmodulin can bind peptide motifs on various proteins

Modulate apoptosis, metabolism, inflammation and immunity