Intracellular Signaling and the Central Dogma

Question 1

What are the 3 ways that intracellular signaling cascades can affect transcription?

Answer 1

1.They can affect transcription factors
2.) They can affect coactivators or co-repressors
3.) They can affect histones remodeling

Question 2

__________ binds a DNA sequence directly to affect transcription.

Answer 2

transcription factor

Question 3

__________/__________ binds a transcription factor to affect transcription (does not bind DNA directly

Answer 3

co-activator / co-repressor

Question 4

True or false.
cAMP activates cAMP-dependent protein kinase (aka PKA)

Answer 4

True

Question 5

PKA is a ____________ protein.

Answer 5

multimeric

Question 6

Which target protein has quicker effects? Transcription factors, adjacent phosodiesterase, or other enzymes?

Answer 6

Other enzymes effect occurs within seconds!

Adjacent phosphodiesterase RAPIDLY lowers cAMP levels to shut off the signal.

Transcription factors effects occur over HOURS

Question 7

To activate transcription regulators, activated PKA enters the nucleus and activates _____________.

Answer 7

CREB = CRE-binding protein

It is a transcription factor for genes with a CRE

Question 8

What co-activator does activated CREB recruit?

Answer 8

CREB-binding protein (CBP)

Question 9

Ca2+/calmodulin-dependent kinases (CaM-Kinase) can also ________________ transcription regulators to increase or decrease transcription.

Answer 9

phosphorylate

Question 10

Protein kinase C (PKC) functions similarly to PKA, it ___________ target proteins.

Answer 10

phosphorylates

Question 11

_______ is a protein activated by receptor tyrosine kinases.

Answer 11

Ras

Question 12

Active Ras triggers a series of activation-via-phosphorylation reactions ending with the activation of _____________.

Answer 12

MAP kinase

Question 13

Is this the correct order?
Active Ras protein (GTP) —>RAF—->MEK—>ERK

Answer 13

yes

Question 14

What does MAP stand for?

Answer 14

mitogen-activated protein

Question 15

What does RAF stand for?

Answer 15

Rapidly Accelerated Fibrosarcoma

Question 16

What does MEK stand for?

Answer 16

Mitogen-Activated Protein Kinase Kinase

Question 17

What does ERK stand for?

Answer 17

Extracellular Signal-Regulated Kinase

Question 18

MAP Kinase (Erk) can enter the nucleus to phosphorylate transcription factors, that activates _________ needed for immediate early genes

Answer 18

transcription factors

Some of these newly translated proteins then turn on other genes

Question 19

A common pathway for growth factors is the _________ pathway

Answer 19

PI 3 Kinase-AKT

Question 20

cAMP PKA
Ca2+  CaM Kinase
Ras  Map Kinase
DAG + Ca2+  PKC
PI 3 Kinase-AKT pathway

These are all second messenger pathways that activate a ____________.

Answer 20

Protein kinase

Question 21

JAK STAT
Smad

These are activated cell membrane receptor pathways that directly activate what?

Answer 21

a transcription factor

Question 23

Wnt-Beta catenin pathway
NF𝜅B

These are pathways involved in regulating what?

Answer 23

proteolysis = breaking down proteins into smaller peptides or individual amino acids.

Question 24

Steroid hormones
Thyroid hormones

These are both what kind of receptors?

Answer 24

intracellular

Question 25

miRNA
lncRNA

These are both non-coding RNA affecting what?

Answer 25

transcription

Question 26

GF binds to receptor (RTK), which activates PI 3 Kinase (phosphoinositide 3 Kinase). PI 3 Kinase adds phosphate groups to phosphatidyl inositol => PIP3  activation of AKT (with help of PDK1)  activation of a wide variety of proteins including mTOR Complex1 => cell growth

Which pathway is this?

Answer 26

PI 3 kinase AKT pathway

Question 27

JAK (janus kinase) phosphorylates and activates transcription factors called ________

Answer 27

STATS

This pathway is more direct than others we’ve looked at

Question 28

True or false
With Wnt signalling, the β-catenin degradation complex is disrupted

Answer 28

true

Question 29

Wnt regulates the proteolysis of what multi-functional protein?

Answer 29

β-catenin

Question 30

Small, hydrophobic ligands don’t need cell surface receptors since they can easily diffuse across the plasma membrane, what are some examples?

Answer 30

Ligands: Steroid hormones, thyroid hormones, retinoids, vitamin D

Question 31

Ligand diffuses into the cell and binds to its receptor to alter the ability of the receptor to control transcription of specific genes.

The receptor is BOTH the __________ receptor AND a __________ factor

Answer 31

intracellular / transcription

A co-regulator is often recruited as well.

Question 32

__RNA associates with proteins to form an RNA-induced silencing complex (RISC)

Answer 32

mi

code for proteins

short

Question 33

Base-pairing of the miRNA can either:

Answer 33

1.) induce mRNA cleavage/destruction
-or_
2.) repress translation

Question 34

miRNAs within a RISC complex act to _________mRNA post-transcription.

Answer 34

SILENCE

Question 35

What type of RNA can:
A) promote gene transcription
B) suppress gene transcription
C) Promote chromatin modification directly
D) Stabilize protein complexes that modify chromatin structure

Answer 35

lcnRNA

do not code for proteins

long

Question 36

lncRNA stands for what?

Answer 36

Long Non-Coding RNA

Question 37

miRNA stands for what?

Answer 37

micro RNA