Dr. White-Genes (when things go right and wrong) Flashcards Preview

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Flashcards in Dr. White-Genes (when things go right and wrong) Deck (64)
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1

What is signal transduction?

cell to cell communication

2

what happens if the lectin gene is knocked out? (mice used as example) What is this an example of?

if leptin is knocked out, the mouse will not think that it is full and will continue eating, resulting in a fat mouse. This is an example of signal transduction.

3

Describe endocrine signaling

long distance signaling, signal goes from bloodstream to distant target cells.
Freely diffusible signal and long lasting

4

Describe paracrine signaling

acts locally and affects nearby cells (not as freely diffusible)
short lived signal

5

Describe synaptic signaling

acts locally and affects cells nearby (not as freely diffusible)
short lived signal
ex: neurotransmitters

6

Describe autocrine signaling

-cells respond to signals that they themselves release to cells of the same type
-cell secretes signal that feeds back and binds to a receptor on its own surface
ex: growth factor in cancer cells

7

Describe direct cell signaling

Ag-presenting cells to T cells
ex: immune cells

8

What does the extracellular domain of the G protein coupled receptor do?

binds to ligand

9

What does the transmembrane domain of the G protein coupled receptor do?

anchors receptor

10

What does the cytoplasmic domain of the G protein coupled receptor do?

associates with G protein

11

G proteins are ______ proteins composed of how many subunits?

heterotrimeric, 3 subunits: alpha, beta, gamma

12

What do the heterotrimeric G proteins do?

regulate target enzymes

13

REVIEW THE PATHWAY OF G PROTEIN SIGNALING

slide 13 of lecture

14

What does adenylyl cyclase do?

generates cAMP which then goes on to interact with it''s target protein to cause a biological response

15

What occurs in cholera?

Cholera toxin modifies G protein by keeping the G alpha protein in the GTP active form indefinitely, making the pathway always active. Cl- and water pump out of cell in intestine, causing severe diarrhea.

16

cAMP interacts with target proteins to cause what?

a biological response

17

cAMP activate ______ which has ____ subunits

cAMP dependent protein kinase (PKA), 4 subunits

18

When 2 cAMP molecules bind to the regulatory subunits of PKA what happens?

release of active C subunits

19

Describe receptor tyrosine kinases (RTKs)

play important role in signal transduction
enzyme linked receptor
used for response to growth factors

20

What are the components of RTKs?

extracellular domain
transmembrane domain
cytoplasmic domain which transmits signal through tyrosine kinase domain and adds phosphates to tyrosine on proteins

21

review signaling by protein phosphorylation

slide 21

22

What happens when a ligand binds to the RTK?

causes conformational change which induces dimerization of two receptor monomers and autophosphorylation occurs

23

Autophosphorlyation of the the RTK causes what?

the receptor to act as a scaffold or docking sites to recruit other proteins to the plasma membrane, outside event (binding to receptor) gets transacted to a response inside the cell

24

review RTK cascade

slides 24-27

25

review JAK-STAT process

slide 28

26

review serine-threonine receptor and smad

slides 29-30

27

when signal is not turned off, Ras is constitutively activated from a point mutation of Gly to ____ and results in what?

Val, resulting in mutation (frequently found in human cancer)

28

What makes cells different?

differences in gene expression

29

describe the helix turn helix DNA-binding domain structural motif

-simplest
-two alpha helices connected by short chain of amino acids that make turn at fixed angle
-longer helix portion= recognition module-DNA binding module
- binds DNA as dimers

30

describe the zinc finger domain

-DNA binding motif includes Zn atom
- binds to major groove of DNA