Lecture 8 Cell Signaling

Question 0

Tyrosine kinase’s have 2 domains, The Catalytic domain is where what happens?

Answer 0

autophosphorylation

Question 1

Gprotein receptors have ___#__ pass membrane receptors?

Answer 1

7

Question 2

Downstream signaling molecules bind Inside or outside of the Catalytic domain?

Answer 2

Outside. Inside the catalytic domain is where the tyrosine kinases are phosphorylating eachother, (ie within the dimer intracellularly)

Question 3

Downstream signaling molecules have domains that bind to specific phosphotyrosine-containing peptides at domains called _________?

Answer 3

SH2 domains

Question 4

name 3 residues on protein kinases that recieve signal/phosphorylation, and take part in autophosphorylation.

Answer 4

Y, T, S

Question 5

What are the two roles of autophosphorylation?

Answer 5

•Phosphorylation of tyrosine in the catalytic domain
increases protein kinase activity.
•Phosphorylation of tyrosine outside the catalytic domain creates binding sites for other proteins that transmit
signals downstream of the activated receptors

Question 6

When are receptor tyrosine kinases unphosphorylated and monomeric?

Answer 6

In the absence of Ligand.

Question 7

T/F and why/whynot?

Cytokine receptors and Tyrosine kinase Receptors can autophosphorylate.

Answer 7

False. Cytokine receptors, cannot and must employ something else to do its autophosphorylation. See that there is not Kinase in the name.

Question 8

•Cytosolic domains of cytokine receptors are associated with kinases such as _____ that do all the dirty work of autophosphorylation.

Answer 8

Jak

Question 9

Jak binds the SH2 site of what signal Tranducer?

Answer 9

STAT (signal Transducer Activator of Transcription)

Question 10

In the camp pathway ATP is converted to _______?

Answer 10

cAMP

Question 11

Which G protein Subunit activates Adenyl cyclase?

Answer 11

alpha

Question 12

cAMP is degraded to AMP by what enzyme?

Answer 12

phosphodiesterase

Question 13

cAMP binds to cAMP dependent ________ _________. Its Activated catalytic subunit is released and translocates to the ________.

Answer 13

protein kinase (kinase A)
nucleus

Question 14

In the cAMP pathway, ultimately to expression genes… the Catalytic subunit of protein kinase A binds to _______ (transcription factor)which is bound to ______ (regulatory sequence).

Answer 14

CREB (CRE Binding prot)

CRE (cAMP response element)

Question 15

Of the pathways, which is know for a Direct and rapid way of turning on a set of genes?

Answer 15

JAK-STAT pathway

Question 16

Of the following in the Jak-STAT pathway, which form Dimers?

Cytokine Receptors, JAK, STAT, CREB

Answer 16

Cytokine receptors and STAT for dimers.

JAK gets close enough to Phosphorylate eachother and the receptors, but do not bind. CREB is in cAMP pathway.

Question 17

How many Phosphorylations are there in the ERK-MAP kinase Pathway? and what are the kinases that do this?

Answer 17

3 Phosphorylations by 3 different protein kinases
RAF (MAP3K)
MEK
ERK (MAPK)

Question 18

Of the 3 different protein kinases in the ERK-MAP pathway,
Which are associated with Ser-Thr and which with Try-Thr prot. kinases?
RAF (MAP3K) Ser-Thr prot. kinases
MEK Try-Thr prot. kinases
ERK (MAPK) Ser-Thr prot. kinases

Answer 18

RAF (MAP3K)
MEK
ERK (MAPK)

Question 19

•Activated MAPK translocates into nucleus and phosphorylates _________?(transcription factor).

Answer 19

Elk-1

Question 20

In the ERK-MAP Kinase pathway, intially in the cell, 2 proteins bind to begin the signal pathway. Also, at the very end of the pathway, 2 proteins are bound by ELK-1 to begin transcription. name the 2 protein bound pairs at both ends of the pathway?

Answer 20

RAS - RAF

SRE- SRF

Question 21

(main thing to know for this pathway) The PIP2 pathway is another secondary messenger that uses autophosphorylation which lead ultimately to gene expression by transcription factors. BUT this is also know for one other special action, the release and mobilization of ___ from the ______ ____?

Answer 21

Ca2+ from the Smooth ER.

Question 22

Their are 5 main players in the PIP2 pathway, that he told us to review the diagram on, but didn’t cover in class? Do you happen to know those players

Answer 22

PLC-gamma –>
PIP2 converted to DAG and IP3 by PLC-gamma
DAG (activates PKC) & IP3 (mobilizes Ca2+)
Protein Kinase C

Question 23

Be able to list the major examples of signaling mechanisms.

Answer 23

Receptor Tyrosine Kinases
Cytokine Receptors (most simplistic)
cAMP Pathway 
ERK- MAP pathway
PIP2 pathway (also Ca2+ mobilization)

Question 24

Describe each of the major examples of cell signaling mechanisms: endocrine, paracrine, autocrine, neurotransmitter, and neuroendocrine.

Answer 24

over a distance through blood
Nearby
self
synapses
Posterior pituitary

Question 25

Be able to list and describe the mechanism of action of cell signaling molecules: receptor-G-protein-effector, enzyme-linked, steroid messengers, and gasses as
messengers

Answer 25

yes you