Biochem Block 1: Cell Signaling (Fulop)

Front 1

What are 5 major cell responses to signals?

Back 1

-cell proliferation
-cell movement
-cell differentiation
-altered metabolic/secretory activity
-cell death

Front 2

What are the 3 signaling defects?

Back 2

1. lack of signaling molecules (diabetes type I).
2. Insensitivity to signaling molecules (diabetes type II).
3. Hyperactivity to signaling molecules (hyperthyroidism)

Front 3

Nicotinic receptors are found in ________

Back 3

skeletal muscle

Front 4

Muscarinic receptors are found in _________

Back 4

muscle cells (think Myo - Muscarinic)

Front 5

What enzyme degrades excess Ach?

Back 5

acetylcholine esterase

Front 6

How does myasthenia gravis work?

Back 6

it's an autoimmune neuromuscular disease in which autoantibodies are produced that IRREVERSIBLY DESTROY THE NICOTINIC ACh RECEPTOR. This makes the muscle unable to contract--droopy face

Front 7

What is the treatment of mysanthenia gravis?

Back 7

because you have low receptor levels, increasing the amount of acetylcholine by introducing REVERSIBLE ACETYLCHOLINE ESTERASE INHIBITORS will make the best use of that low receptor count

Front 8

In insecticides and nerve gasses like Sarin and VX, what enzyme is affected? What is the treatment?

Back 8

acetylcholine esterase is irreversibly inhibited--large amounts of Ach--prolonged contraction--deadly (especially in heart)

treatment - Ach receptor antagonists (blockers) like Atropine

Front 9

What do cytokines do?

Back 9

produced by immune system to regulate immune function (interferons, interleukins)

Front 10

What do eicosanoids do?

Back 10

produced in response to injury or inflammation (prostaglandins)

Front 11

Vitamin D3, steroids and thyroid hormone are water ___________.

Back 11

insoluble

Front 12

Short distance hormone signaling involving the same cell (or same types of cells) is called

Back 12

autocrine signaling

Front 13

Short distance hormone signaling involving different types of cells is called

Back 13

paracrine signaling

Front 14

An antigen presenting to a T cell is an example of ____________ cell signaling

Back 14

contact-mediated

Front 15

The neuromuscular junction is an example of _____________ signaling.

Back 15

paracrine

Front 16

If a chemical signal is released in low concentrations, its receptor has ________ affinity for that signal

Back 16

high

Front 17

Neurotransmitters are released in high concentrations with very short half lives. Therefore their receptors have a _________ affinity for neurotransmitters

Back 17

relatively low

Front 18

Prostaglandins are examples of _________ cell signaling.

Back 18

autocrine

Front 19

Endocrine signals have ________ half lives

Back 19

long, on the order of mins, hours or days

Front 20

Endocrine signals cause a (slow, fast) cell response

Back 20

slow

Front 21

Hydrophobic molecules tend to have a __________ (intracellular, extracellular) receptor while hydrophilic molecules tend to have a _________ receptor

Back 21

-intracellular because they can pass the hydrophobic membrane

-extracellular, cannot pass membrane

Front 22

The 4 type I nuclear receptor steroids are

Back 22

-coristol
-aldosterone
-progesterone
-testosterone

(CAPT is number 1)

Front 23

The type III nuclear receptor reacts to the steroid hormone

Back 23

estradiol

Front 24

Dexamethasone is an anti-inflammatory steroid drug that acts through the ______________ signaling pathway

Back 24

type I and type III intracellular

Front 25

Thyroid hormone, vitamin D3 and retinoic acid all act through ________________ receptors.

Back 25

type II nuclear

Front 26

Corepressors and coactivators are involved in the _______________signaling pathway

Back 26

type II nuclear receptor

Front 27

Chemical signals are converted into electrical signals by what kind of receptor?

Back 27

ion-channel linked receptor

Front 28

An example of an ion-channel linked receptor is the

Back 28

nicotinic ACh receptor

Front 29

The drugs _____________ target adenergic receptors (that work through a g-protein mechanism) to treat cardiac arrhythmias.

Back 29

beta-blockers

Front 30

The muscarinic ACh receptor, Adenergic (epinepherine, norepinepherine) and the glucagon receptor are all considered ____________ receptors.

Back 30

g-protein linked

Front 31

The insulin receptor, most growth factor receptors, interleukin 1 receptor and integrins (ECM receptors) are all what kind of receptor?

Back 31

enzyme-linked receptors

Front 32

In the nicotinic acetylcholine receptor, a ligand-gated ion channel receptor, _____________, causing muscular contraction

Back 32

Na+ moves into cell

Front 33

In the muscarinic acetylcholine receptor, a G-protein linked receptor, ________________, causing a decrease in the contraction of the heart

Back 33

K+ moves out of the cell

Front 34

During INTRAcellular signaling, the activity of proteins is modified by ____________.

Back 34

kinases (enzymes that add phosphate groups to proteins)

Front 35

The enzyme opposite to a kinase is a ____________.

Back 35

phosphatase (removes phosphate group, while a kinase adds a phosphate group)

Front 36

The balance between the activites of the enzymes __________ and _________ determine intracellular signaling.

Back 36

kinases and phosphatases

Front 37

Second messengers are associated with what receptor?

Back 37

g-protein linked

Front 38

Second messengers activate ______.

Back 38

protein kinases

Front 39

Why don't enzyme/enzyme-linked receptors use second messengers?

Back 39

the receptors have their own kinase activity. second messengers activate protein kinases, but if the receptor is already a protein kinase (as in the case of enyzme receptors) a second messenger isn't needed. The enzyme is a kinase

Front 40

Cholera toxin works by transferring a __________ group to a stimulatory _______ subunit, which prevents the ______________. This causes adenyl cyclase to remain _____________, causing extreme salt water efflux in gut epithelium (diarrhea).

Back 40

-ADP ribose group

-Gsalpha

-hydrolysis of GTP to GDP.

-constantly active

Front 41

Pertussis toxin transfers an _________ group to an inhibitory ________ subunit, which deactivates its ability to inhibit _____________. This results in high ______ levels, which cause increased mucus secretion in airway epithelium.

Back 41

-ADP ribose
-Gialpha
-adenyl cyclase
-cAMP

Front 42

cAMP-dependent protein kinase A has ___ subunits and is normally inactive. It depends on ________ to activate its catalytic subunits.

Back 42

-4

-cAMP

Front 43

G-protein linked receptors can activate protein kinase 3 through a mechanism that uses ______ second messengers. What process in the body uses this mechanism?

Back 43

3. IP3, DAG, and finally Ca2+

this is seen in alpha adrenergic receptors on smooth muscle cells that mediate vasoconstriction

Front 44

Only in the case of the muscarinic ACh receptor, channel activation is performed by the _________ subunit, not the ______ subunit and there are no ________________ involved.

Back 44

- beta-gamma
-alpha
-second messengers

Front 45

The tyrosine kinase, JAK-STAT and serine-threonine kinase receptors are all _________________ receptors.

Back 45

enzyme or enzyme-linked

Front 46

What are the 3 steps to enzyme/enzyme-linked receptor signaling?

Back 46

1. receptor has to DIMERIZE
2. phosphorylation
3. phosphorylated dimerized receptor binds a SIGNAL TRANSDUCER PROTEIN

Front 47

Cytokines (interleukins, immuno stuff) use ________ receptors for signaling.

Back 47

JAK-STAT

Front 48

In JAK-STAT receptors, the JAKs are

Back 48

tyrosine kinases that associate with the receptor and phosphorylate it

Front 49

In JAK-STAT receptors, the STATs are

Back 49

signal transducing proteins

Front 50

In serine-threonine kinase receptors, __________ is the signal transducer protein that binds to the receptor.

Back 50

R-Smad

Front 51

Tyrosine kinase receptors initate 3 important pathways which are...

Back 51

1. MAP kinase
2. PLC-gamma (phospholipase C)
3. PI-3 kinase

Front 52

When blood glucose is high, insulin stimulates glucose metabolism by 3 things:

Back 52

1. GLUT-4 glucose transporters pop up all over membrane
2. genes for glucose metabolism are upregulated (transcription/translation)
3. excess glucose stored in glycogen or fatty acids

Front 53

Because signaling pathways do not act alone, alternative pathways can partially restore the function of impaired pathways. In type II diabetes, activating __________________ induces the transcription of genes involved in glucose metabolism.

Back 53

peroxisome proliferator-activated receptor (PPAR)

Front 54

ACh is destroyed by the enzyme ________________.

Back 54

acetylcholine esterase

Front 55

cAMP, a second messenger, is destroyed by _______________.

Back 55

phosphodiesterase

Front 56

Explain how hyperthyroidism works

Back 56

In hyperthyroidism (Graves' disease), autoantibodies increase TSH receptors on the thyroid gland, producing more thyroid hormone. This thyroid hormone participates in a negative feedback loop that inhibits the hypothalamus and pituitary gland production of TSH, but since the auto-antibodies are still acting on the thyroid gland the thyroid keeps on producing thyroid hormone and the negative feedback loop is rendered useless. = EXCESS THYROID HORMONE

Front 57

Type I and III nuclear receptors first bind to a molecule in the _______, and then are transported into the nucleus.

Back 57

cytosol

Front 58

Beta blockers act through a ____________ receptor to inhibit _______ production

Back 58

-g protein linked

-cAMP

Front 59

Adenosine and PGE1 are signals that ___________ cAMP production through _______________ receptors. Although they have the same action, they are not considered ______________.

Back 59

-inhibit

-g-protein linked

-not beta blockers

Front 60

Which signaling pathway induces GLUT-4 to go to the cell surface to upregulate cell uptake of glucose in a cell being affected by insulin?

Back 60

PI-3 kinase

Front 61

Which signaling pathway induces upregulation of transcription and translation of glucose metabolism genes in a cell being affected by insulin?

Back 61

MAP-kinase

Front 62

Which signaling pathway induces glycerol/fatty acid storage for excess glucose in a cell being affected by insulin?

Back 62

PLC-gamma