Hormones II Flashcards
Non-polar group of hormones that have receptors inside the cell
Group I
Polar hormones with receptors at the plasma membrane
Group II
The primary messenger in signal transduction pathway
Hormone
Small molecules in complicated networks within the cell which results to signal amplification and alteration of intracellular molecules creating a response
Second messengers
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
This is a short sequence of DNA that can bind to a specific hormone receptor complex and therefore regulate transcription.
Hormone Response Element
The HRE is found within the ______ of a gene
promoter
Give the “SDAT” group I hormones
Steroid
vitamin D
vitamin A
Thyroid
True or False:
Small uncharged polar molecules are unable to pass the plasma membrane
False:
Although polar, small uncharged molecules are able to pass
The first reaction in the process of Ligand-receptor complex
activation reaction
Glucocorticoid ligand-receptor binding results in the dissociation of:
hsp90
Accelerated gene transcription typically ensues when ________ proteins bind with DNA-bound ligand receptors
coactivator
The tonic repressor of gene transcription in the 2nd mechanism of receptor activation
Receptor-corepressor complex
What kind of hormone is Adapalene
Retinoid
DNA sequence for cAMP
TGACGTCA
DNA sequence for Glucocorticoids, Progestins, Mineralocorticoids, Androgens effectors
GGTACA nnn TGTTCT
inverted repeat
DNA sequence for estrogen effectors
AGGTCA - TGACCT
inverted repeat
DNA sequence for vitamin D, vitamin A and thyroid hormone effectors
AGGTCA n(1-5) AGTCA (direct repeats)
Give the 4 classes of plasma membrane receptors
Ion-channel linked
GPCR
Catalytic receptor
Transmembrane receptor
Mechanism of action of Group II hormones
Generation of Intracellular signals
- Reception
- Transduction
- Response
α subunit of G protein is inactivated when bound to
GDP
Which G protein subunits are connected to the cell membrane?
β and γ
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
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
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?
4
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)