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Flashcards in Enzyme-linked receptors Deck (30)
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1
Q

How does ANP activateit’s receptor?

A

ANP causes Guanylyl Cyclase to dimerize

2
Q

What does the binding of ANP and dimerization of guanylyl cyclase activate?

A

GTp -> cGMP

3
Q

What does cGMP activate?

A

Protein kinase G

4
Q

What is the function of protein kinase G?

A

Phosphorylates & activates proteins to mediate hormone function

5
Q

How does ANP concentration affect angiotensin?

A

ANP inhibits angiotensin and aldosterone

6
Q

Where is ANP released from?

A

Atrium

7
Q

How does ANP (ANF) decrease blood volume?

A

Inhibits Angiotensin & aldosterone to prevent Na+ and water retnetion
Vasodilation

8
Q

What receptor is capable of phosphorylating itself?

A

Tyrosine kinase

9
Q

Name an example of a ligand that binds to a tyrosine kinase receptor

A
Insulin
Fibroblast growth factor
Vascular endothelial growth factor
Nerve growth factor
Epithelial growth factor
Platelet derived growth factor
10
Q

What are the 2 pathways that tyrosine kinase receptors use for phosphorylation?

A

Insulin Receptor Substrate 1 pathway

MAPK pathway

11
Q

Describe the IRS-1 pathway

A

Activated tyrosine kinase receptor associates with IRS-1 and activates phospho-inositol-3-kinase (PI3K)

PI3K mediates vesicles that contain GLUT4

12
Q

Describe the MAPK pathway

A

Son of Sevenless adapter protein associates with tyrosine kinase

RAS-GTP activates MAP-kinase pathway
MAPKKK
MAPKK
MAPK

Phosphorylated MAPK translocates to nucleus and activates jun, fos, myc transcription which activate GLUT4

13
Q

What is RAS?

A

Protein with intrinsic GTPase used to relay signals to nucleus

14
Q

What is the active form of RAS?

A

RAS-GTP

15
Q

How does a RAS mutation cause cancer? Why is it called the proto-oncogene

A

RAS that lacks GTPase activity cannot turn itself off and continues signaling for cell proliferation

16
Q

What is the purpose of the GLUT2 receptor?

A

Glucose binds to GLUT2 to signal the release of insulin from Beta cells

17
Q

What is the difference between Insulin deficiency and insulin resistance?

A

Deficiency has defective Beta cells

Resistant has defective GLUT4. More insulin than normal is needed to activate GLUT4 receptors

18
Q

What is hyperlipemia and why is it a symptom of diabetes?

A

Excess fat in the blood

Caused by excess mobilization of fatty acid

19
Q

What does the excessive mobilization of fatty acids result it?

A

Ketosis

Sweet breath caused by acetone

20
Q

What is the purpose of primary response gene bcl2?

A

Ensure that RBCs survive in the bone marrow long enough to mature

21
Q

What is JAK2?

A

An auto-phosphorylating tyrosine kinase receptor

22
Q

What are the 2 pathways for Erythropoietin receptors?

A

JAK2/STAT

JAK2/MAPK

23
Q

Describe the JAK2/STAT5 pathway

A

Binding of EPO dimerizes receptor
Non-receptor tyrosine kinase binds to dimerized receptor (JAK2)

JAK2 phosphorylates STAT5
STAT5 translocates to the nucleus to begin transcription of bcl2

24
Q

Describe the JAK2/MAPK pathway

A

EPO dimerizes receptor
Non-receptor tyrosine kinase JAK2 binds to receptor

SOS binds to JAK2

SOS produces RAS-GTP and activates MAPKKK
MAPKK
MAPK

MAPK translocates to nucleus and acitvates myc, fos, jun

25
Q

Name a secondary gene primary transcription factors activate transcription for

A

Cyclin D

26
Q

What organ produces erythropoietin?

A

Kidney

27
Q

What stimulates production of EPO?

A

Reduction in pO2 (erythrocyte count low or high altitude)

28
Q

What is the function of EPO?

A

Increase erythrocyte count by stimulating proliferation in bone marrow

29
Q

What is the purpose of recombinant human EPO? (rhEPO)

A

Stimulates red blood cell development

30
Q

What are side effects of rhEPO?

A

Increased blood viscosity
Increased chance of embolism

Long term use of rhEPO will shut down natural EPO production