Chapter Six

Question 1

What are IEGs?

Answer 1

immediate early genes
expression happens even when protein synthesis is blocked
indicates transcription factors regulating expression of these genes are already present in the serum starved cells

Question 2

What are DEGs?

Answer 2

delayed early genes

are activated by IEGs

Question 3

What are 2 ways DEGs are activated by IEGs?

Answer 3

1. mRNAs, polyribosomes, transcription factors, DEGs

2. activation of preexisting translation factors, polyribosomes, transcription factors, DEGs

Question 4

What shape do cells take in presence of serum?

Answer 4

actin stress fibers & focal adhesions

Question 5

What shape do cells take in absence of serum?

Answer 5

cortical actin

Question 6

What is an ommatidia?

Answer 6

light sensing units in Drosophila eye

formed from series of “seven cells”

Question 7

What controls many cytoplasmic signaling proteins?

Answer 7

tyrosine phosphorylation

Question 8

What is the domain structure of src?

Answer 8

SH1, 2, 3

Question 9

What is the function of SH2?

Answer 9

binding site for phosphotyrosine & side chains of flanking AAs

Question 10

What is the function of SH3?

Answer 10

proline rich oligopeptides

Question 11

What are signal transducting proteins attracted to?

Answer 11

phosphate receptors

Question 12

Why are SH2 & 3 important?

Answer 12

explain how GF receptors activate Ras & acquire signaling specificity

Question 13

What are the 3 pathways of Ras?

Answer 13

1. Ras, Raf, MAP kinase pathway
2. P13 kinase pathway
3. Ral-GEF

Question 14

What is the target of the P13 kinase pathway?

Answer 14

inositol lipids & Akt/PKB kinase (cell growth)

inositol = 2nd messenger/intracellular hormone

Question 15

What is the function of Ral?

Answer 15

controls cytoskeleton

Question 16

What is the function of the Jak-STAT pathway?

Answer 16

allows signals to be transmitted from the PM directly to the nucleus
constitutive activation of STAT3

Question 17

What are the 3 functions of integrin signaling?

Answer 17

1. physically link cells to ECM
2. inform cells if tethering to certain ECM components has been achieved
3. facilitating motility by making & breaking contacts w the ECM

Question 18

Cell adhesion receptors emits signal that converge with?

Answer 18

GF receptor signals

Question 19

What is the role of the Wat-beta-catenin pathway?

Answer 19

cell proliferation

Question 20

How if beta-catenin signaling regulated?

Answer 20

GSK-3beta = high levels of beta-catenin

levels increase in presence of carcinogens

Question 21

What happens when RTK is shut down?

Answer 21

physical interalization of receptor molecules preventing them from binding ligand in EC space

Question 22

What is the role of nuclear factor-kB (NF-kB) signaling system?

Answer 22

regulates innate & adaptive immune response

Question 23

How does contact dependent signaling work?

Answer 23

cleave of notch at 2 sites following ligand binding liberates cytoplasmic frag to migrate to nucleus and function as part of transcription factor complex

Question 24

What are 3 molecular mechanisms that create oncogenes?

Answer 24

1. mutation
2. amplification
3. chromosomal rearrangement

Question 25

What factors determine lifetime of activated state of signaling molecules?

Answer 25

negative and positive feedback

GPCRs