Hormones II Flashcards by Venice Camille Patricio

Non-polar group of hormones that have receptors inside the cell

Group I

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Polar hormones with receptors at the plasma membrane

Group II

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The primary messenger in signal transduction pathway

Hormone

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Small molecules in complicated networks within the cell which results to signal amplification and alteration of intracellular molecules creating a response

Second messengers

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Functions of signaling molecules include the following except:
A. Control cytoskeleton-associated events
B. Modulate ionic composition
C. Regulate cell division
D. Influence cellular metabolism
E. NOTA

E. NOTA

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This is a short sequence of DNA that can bind to a specific hormone receptor complex and therefore regulate transcription.

Hormone Response Element

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The HRE is found within the ______ of a gene

promoter

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Give the “SDAT” group I hormones

Steroid
vitamin D
vitamin A
Thyroid

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True or False:

Small uncharged polar molecules are unable to pass the plasma membrane

False:

Although polar, small uncharged molecules are able to pass

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The first reaction in the process of Ligand-receptor complex

activation reaction

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Glucocorticoid ligand-receptor binding results in the dissociation of:

hsp90

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Accelerated gene transcription typically ensues when ________ proteins bind with DNA-bound ligand receptors

coactivator

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The tonic repressor of gene transcription in the 2nd mechanism of receptor activation

Receptor-corepressor complex

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What kind of hormone is Adapalene

Retinoid

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DNA sequence for cAMP

TGACGTCA

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DNA sequence for Glucocorticoids, Progestins, Mineralocorticoids, Androgens effectors

GGTACA nnn TGTTCT

inverted repeat

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DNA sequence for estrogen effectors

AGGTCA - TGACCT

inverted repeat

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DNA sequence for vitamin D, vitamin A and thyroid hormone effectors

AGGTCA n(1-5) AGTCA
(direct repeats)

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Give the 4 classes of plasma membrane receptors

Ion-channel linked
GPCR
Catalytic receptor
Transmembrane receptor

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Mechanism of action of Group II hormones

Generation of Intracellular signals

Reception
Transduction
Response

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α subunit of G protein is inactivated when bound to

GDP

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Which G protein subunits are connected to the cell membrane?

β and γ

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Which of the following is true of G-protein-coupled receptors?
A. They are 7 α-helical hydrophobic cell membrane-spanning domains
B. They are receptors that signal and couple through to effector G-proteins
C. Binds Group II hormones
D. Largest family of cell surface receptors
E. AOTA

E. AOTA

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Which of the following does not inhibit Adenylyl cyclase?
A, ACh
B. β-Adrenergics
C. α2-Adrenergics
D. Angiotensin II
E. Somatostatine

B. β-Adrenergics

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cAMP is terminated by

Phosphodiesterase

Cholera toxin causes ADP _____ of α stimulatory subunit of G protein

ribosylation

Pertussis toxin acts through ADP ribosylation of:

α inhibitory subunit that stops dissociation of α from βɣ subunits = unopposed activity of α stimulatory subunits in the cell

``` α stimulatory leads to: A. hyperpolarization B. depolarization C. close Ca++ channels D. open K+ channels ```

B. depolarization

DAG activates which Secondary effector?

Protein kinase C

``` Activated G-alpha protein can act on: A. Adenylyl cycles B. PLC C. Ion channel D. AOTA ```

D. AOTA

The most common 2nd messenger

cAMP

Integrin conformation and cell adhesion require the action of which 2nd messenger?

cGMP

``` Phosphorylation usually results in functional change of the target protein that includes: A. Changing enzyme activity B. Modifying cellular function C. Associating with other proteins D. AOTA ```

D.AOTA

In prokaryotes, cAMP binds to ____ that binds directly to DNA which influences gene expression

CAP

The activated catalytic subunits of PKA transfers phosphorylates which amino acid residues of proteins?

Serine and Threonine this forms a phosphoprotein

This is a weak activator of transcription that is phosphorylated by PKA for it to bind with CBP (an activator)

cAMP Response Element Binding Protein (CREB)

Phosphorylated CREB with CBP and HAT binds to which enhancer element to speed up transcription?

cAMP-responsive DNA element (CRE)

These derivatives increase intracellular cAMP by inhibiting PDE (ex. caffeine)

Methylxanthine derivatives

Phosphoprotein phosphatase may be regulated by the following except: A. Phosphorylation and dephosphorylation reactions B. Protein-hormone interactions C. Hormones D. NOTA

B. Protein-hormone interactions should be protein-protein interactions

Type of phosphatase that is implicated in regulation of glycogen synthase, glycogen phosphorylase, phosphorylase kinase

Type 1 phosphatase

Insulin will do everything to ________ enzymes for fed state: A. dephosphorylate B. phosphorylate

A. dephosphorylate

Glucagon will do everything to _________ enzymes for fasting state A. dephosphorylate B. phosphorylate

B. phosphorylate

``` The soluble form of Guanylyl cyclase is: A. Homodimeric form B. Targeted by ANP C. Targeted by BNP D. Targeted by NO ```

D. Targeted by NO → Soluble form (Heterodimeric form) ▪ Target of Nitroprusside, Nitroglycerin (NTG), Nitric Oxide (NO), Na-nitrite, Na-azide to increase cGMP − All cause smooth muscle relaxation which leads to vasodilation − Drugs which increase cGMP promotes smooth muscle relaxation (vasodilatory)

``` Which of the following is true of Sildenafil? A. Increase degradation of cGMP B. inhibits cGMP PDE4 C. directly increase cGMP D. promotes smooth muscle relaxation ```

D. promotes smooth muscle relaxation Sildenafil (Viagra) is an example of cGMP PDE5 inhibitor to increase cGMP = Sildenafil does not directly increase cGMP but it prolongs its life through inhibiting its degradation by the action of phosphodiesterase

Activation of membrane bound homodimeric form of guanylyl cyclase results in A. natriuresis B. vasodilation

A. natriuresis

If the hormone binds with the receptor that stimulates the Gq, it will also stimulate neurotransmitter ligands:

``` HAVMnM Histamine Alpha 1 Vasopressin 1 Muscarinic 1 and Muscarinic 3 ```

Which second messenger activates PKC activity depends on Ca++

1,2-Diacylglycerol

Second messenger that is an effective releaser of Ca++ from ER

Inositol triphosphate

How many occupied Ca++-binding sites in calmodulin in order to induce conformational change?

``` Phospholipid present in the cell membrane is cleaved by the phospholipase C gamma into 2 parts: Head = Tail = ```

``` Head = IP3 Tail = DAG ```

Which of the products of PIP2 is the potent activator of PKC?

DAG

Kinases for EGF, NGF, Insulin and IGF preferentially phosphorylate which amino acid residues?

Tyrosine

True of false? | Too much insulin can cause hyperkalemia

False: | Too much insulin can cause hypokalemia since it transports K+ into insulin-Sn cells with glucose and amino acids

Which of the following is a result of delayed action of Insulin? A. Increased protein synthesis B. Increased mRNAs for lipogenic and other enzymes C. Increased transport of glucose, amino acid and K+ in the insulin secreting cells D. Activated glycogen synthase

B. Increased mRNAs for lipogenic and other enzymes

Which subunit of the insulin receptor contains the tyrosine kinase?

β subunits

First protein to be phosphorylated by activated tyrosine kinase from the binding of the receptor to insulin which is responsible in activating PI-3

IRS-1

This catalyzes the addition of phosphate group to the membrane lipid PIP2 in the insulin mechanism pathway

PI-3

This catalyzes phosphorylation of key protein ins the insulin mechanism pathway, leading to increased glycogen synthase activity and recruitment of GLUT 4

Akt

The second major pathway after PI-3 kinase utilizes this enzyme that is directly regulated by AA level

mTOR

Which pathway is taken by PI-3 kinase to stimulate mitosis?

Mitogen-Activated Protein Kinases

What enzyme links the insulin-receptor activation to actions

PI-3 kinase

``` Which of the following is influenced by PI-3 kinase? A. PDK1 B. mTOR C. GRB2 D. MAPK pathway ```

All of that

Receptor pathway used by cytokinese

JAK/STAT pathway

``` Which of the following does not utilize JAK/STAT Pathway? A. GH B. PRL C. Insulin D. cytokines ```

C. Insulin

Which part of the activated cytokine receptor binds with STAT proteins

phosphotyrosine complexes

``` Which occurs first upon phosphorylation of STAT protein? A. STAT dimerizes B. STAT translocates to nucleus C. STAT binds to specific DNA elements D. STAT regulates transcription ```

A. STAT dimerizes

The phosphotyrosine residues of the receptors linked to Jak kinases also bind to several _______, which result in activation of the MAP kinase pathway

SH2 domain-containing proteins (X-SH2)

The first important interaction before generating a signal within the cell

Hormone-receptor interaction

Subunits of the Heterodimer complex for the NF-kB Pathway

p50 | p65

This receptor pathway regulates cellular behaviors such as inflammatory response, growth, and apoptosis

NF-kB Pathway

The inhibitor of NF-kB bby sequestering p50 and p65 subunits in the cytoplasm

IkB

What phosphorylates IkB to free up NF-kB?

IkK

This masks the nuclear localization signal of NF-kB

IkB

Transcriptional regulation by NF-kB is mediated by:

coactivators

Which of the following is not an action of glucocorticoid in the NF-kB pathway? A. Increase Iκβ mRNA resulting to more Iκβ protein that will sequester NFKB in cytosol B. Competes with NFKB for binding to coactivators C. Binds to p50 subunit of NFKB, inhibits its activation D. NOTA

C. Binds to p50 subunit of NFKB, inhibits its activation should be p65

An assembly of DNA elements and complementary, cognate DNA-bound proteins that interact through protein–protein interactions with coactivator or corepressor molecules

Hormone Response Transcriptional Activation Unit

The DNA Binding Domain of nuclear receptors has what binding motifs?

2 zinc finger binding motifs

The target response element direct repeats w/ 3, 4, 5 NT spacer regions specifies binding of which hormones respectively to the same consensus response element?

vit. D, thyroid, Retinoic acid

Which part of the nuclear receptor binds the HRE?

Centrally located DBD

Which part of the nuclear receptor binds hormones/metabolites w/ selectivity?

LBD

Which part of the nuclear receptor provides flexibility to the receptor, so it can assume different DNA-binding conformations

Hinge region

This provides for distinct physiologic functions of nuclear receptors through binding of different coregulator proteins

AF-1 of the amino terminal region

Which hormones utilize homodimer nuclear receptors?

Steroid hormones

Which hormones utilize heterodimer nuclear receptors?

Vit D & A and Thyroid hormones

To which portion of CREB does CBP bid to?

Phosphorylated Serine 137

This serves as the initial signal for members of the nuclear receptor family.

Ligand-receptor complex (hormone-receptor complex)