Week 3 Flashcards
In autosomal dominant disorders, for related, unaffected individuals (no info on parents available), you cannot determine genotype without test
TRUE OR FALSE
True
In autosomal dominant disorders, for unrelated individuals (married in), you cannot assume that they are homozygous normal
TRUE OR FALSE
FALSE - you can UNLESS dz frequency is over 1/20
In FH, what is the chance that individuals are non-penetrant heterozygotes?
1/500
In autosomal dominant disorders, you can assume that affected individuals are heterozygotes unless what? (2)
- both parents affected
- dz frequency >1/20
In autosomal dominant disorders, disease frequency is equal to?
2q (heterozygote frequency)
In autosomal recessive disorders, disease frequency is equal to?
q^2
In autosomal recessive disorders, carrier frequency is equal to?
2q
In an autosomal recessive disorder, if there are NO affected individuals in a sibship and you know that at least ONE of parents is a carrier, what is the probability that an UNAFFECTED child is a carrier?
1/2
In an autosomal recessive disorder, if there ARE affected individuals in a sibship OR you know that BOTH of the parents are carriers, the probability that an UNAFFECTED child is a carrier is?
2/3
In an autosomal recessive disorder, if one parent is homozygous affected and you do not know the carrier status of the UNAFFECTED, UNRELATED spouse, probability of an AFFECTED child is
1/2X the carrier frequency (= q)
When should you recommend carrier testing to an unaffected, unrelated spouse?
When other parent is homozygous affected or if they are a known carrier
In autosomal recessive disorders, affected individuals are often compound heterozygotes unless what?
There is cosanguinity
What protein is affected in cystic fibrosis?
cystic fibrosis transmembrane regulator (chloride channel in lungs and pancreas)
OCA1 is caused by what defect in the phenylalanine metabolism pathway?
Dopamine –> Melanin (catalyzed by tyrosinase)
How common is OCA1?
1/40K are affected, 1/100 are carrier
How does calcium get into the cell to raise cytosolic levels in
- nerve cell
- regular cell
- cardiac muscle cell
1) signal depolarizes PM –> ca++ channels open
2) signal activates receptor –> PLCB stimulated via Gq protein –> Ip3 produced –> Ca++ released from ER
3) Signal depolarizes cell and voltage gated channels open
Describe how foot odor is detected (6 steps)
1) Odorant binds to GPCR on olf neurons
2) Activates Golf protein (GDP–>GTP)
3) Alpha subunit activates adenylyl cyclase
4) cAMP produced
5) cAMP opens Na+ channels
6) Na+ influx into cell
Describe how the eye works in response to light
Rhodopsin is activated which activates Gt which increases PDE which decreases cGMP. Na+ channels close so cell is repolarized.
Describe how the eye works in response to dark
Rhodopsin is inactivated which inactivates Gt which decreases PDE which increases cGMP - Na++ channels open so the cell is depolarized
In GPCR densitization, activated GPCR sitmulates Grk to phosphorylate GPCR on multiple sites. This ATP-driven reaction allows what to bind and densitize the GPCR?
ARRESTIN! :D
What are the five classes of NZ linked receptors
1) receptor tyrosine kinase (RTKs)
2) RTK assoc receptors
3) receptor like protein tyrosie phosphatases
4) receptor/guanylylcyclase
5) receptor ser/threonine kinases
Epidermal growth factor, insulin, nerve growth factor, platelet derived growth factor, MCSF, fibroblast growth factors, ephrins, and vascular endothelial growth factors all act via ___________________
receptor tyrosine kinases
How do ligands induce dimerization? (3 ways)
1) ligand is a dimer with each subunit containing one receptor binding domain
2) monomeric signaling protein forms multimers by binding to heparin sulfate proteoglycans to crosslink its receptor
3) in contact dependent signaling, clusters formed in PM of signaling cell and then crosslink the receptors on target cell
Dimerization and autophosphorylation of receptor tyrosine kinases has what two effects?
1) phosphorylation @ some tyrosines promotes complete activation of kinase domains
2) phosphorylation @ tyrosines in other parts of receptor generates dockig sites for intracellular proteins –> form complexes that broadcast signals
PI3-kinase makes ______________ in the plasma membrane which are required for several signaling pathways
PIP2 and PIP3
______ inactivates Ras pathways while ______ activates Ras pathways
GAP, GEF
PLC-y produces _______ and _______
DAG, IP3
Describe a generic Ras-MAPK pathway
4) Activated Ras recruits MAPKKK (raf) to PM and activates it*
5) Ras recruits MAPKK (mek) to PM and activates it*
6) Ras activates MAPK (erk) *
7) Erk phosphorylates proteins, protein kinases, transcription regulators etc to cause changes in cell behavior*
- ATP catalyzed
What is the major function of PI3 kinase?
Stimulate cell growth
Generation of PIP2 and PIP3 by PI3 kinase generates docking sites for signaling proteins that have ___________________
PH domains
Describe PI3 kinase signaling pathway that leads to B cell activation
B cell receptor binds to PI3 kinase which produces PIP3. BTK binds to PIP3 via PH domain. PLC-y is activated and produces IP3 and DAG. Calcium is released from the ER –> activation of downstream pathways lead to clonal expansion then activation, translation, and regulated exocytosis of Igs
Describe X-linked agammaglobinemia
- mutation
- manifestations
- treatment
- caused by mutation in gene that codes for BTK, most common is mutation in PH domain that prevents BTK from binding to PIP3
- very low serum Ig levels, lack of plasma cells in secondary lymphoid organs
- tx: ABX and passive IgG therapy
PI3 kinase promotes cell survival via phosphorylation and activation of Akt protein which inactivates ______ so that it cannot bind to and inhibit the ______________. This leads to promotion of cell survival
Bad, apoptosis inhibitory proteins
Akt protein is phosphorylated and activated by ______ and ________
PDK1 and mTOR
Which of these is not a cytokine
a) interferon
b) interleukin
c) tumor necrosis factor
d) all of above are cytokines
d
The SRC family belongs to non-receptor ___________
tyrosine kinases
JAKs cross phosphorylate each other on tyrosines once their associated receptors bind to a cytokine, then _______ dock on receptors and are phosphorylated by the JAKS as well
STATs
Once STATs are phosphorylated, they dissociate from receptor and dimerize via _____ domain which allowed the to translocate to nucleus and activate gene transcription
SH2
In rheumatoid arthritis, pathological lesions driven by TNF-alpha induced production of inflammatory mediators that is mediated by transcription factor ________________
NF-kappa-B
in the NF-kappa-B pathway, binding of TNF-alpha causes rearrangement and activation of a protein kinase that phosphorylates and activates ____ which then phosphorylates ____ into two serines. This marks protein for ubiquitylation and degradation in proteasomes. _____ is released and translocated into nucleus where it stimulates transcription.
IKK, IKB, NFKB
______ is major co-inflammatory cytokine that activates NF-KB pathway
TNF-alpha
Crohn’s disease is initiated by an inappropriate innate and acquired immune response to normal enteric flora, which is primarily driven by ________ and macrophage dependent chronic activation.
TNF-alpha
Infliximab blocks action of _____ by binding to it and preventing it from signaling to its receptors on cell surfaces, and has been approved to treat autoimmune diseases
TNF-alpha
Group each category below by type of receptor
a) cAMP, cGMP, DAG, IP3, Ca++
b) Ras activation, MAPK pathway
c) Src, Tyr phosphorylation, PI phosphorylation, JAK stats, NF-kappa-B
a) GPCRs
b) RTKs
c) NZ linked receptors
By end of embryonic period (weeks 3-8), _____________ system is fully functional and developed
cardiovascular
Define safety pharmacology
relatively new discipline that focuses on mechanism of action of unwanted actions and drugs
Ibuprofen is a ____________ name whereas Advil or Motrin would be a ________________
generic name, trade name
The _________ name of a drug is listed in one of the following publications: 1) US Pharmacopoiea, National Formulary, US Adopted Names
official
In 1937, sulfaniimade liquid form was released and led to deaths because solvent was never tested. This prompted passing of Food Drug and Cosmetic act in 1938. What were 3 actions of this act?
- enforced labeling and safety of drugs
- assigned enforcement to FDA
- required NDA (new drug application)
In 1960s, thalidomide caused severe birth defects in newborns. The Harris-Refauver Amendment was passed in 1962 and enforced what (3)
- proof of efficacy
- required investigational new drug application prior to clinical testing
- clinical trials are done AFTER animal testing, full consent required, full details of investigations
What were the lessons learned from recent TGN1412 disaster that results in all human participants suffering a cytokine storm?
- During first human trial, do not give all patients drug simultaneously
- Incorporate NOEL (no observed effect level) with MABEL (minimum anticipated bio effect level) to decide dose
After lab and animal testing, the drug sponsor submits what application to FDA to begin phase I of human trials?
Investigational New Drug