Lecture 8 Cell Signaling Flashcards
Tyrosine kinase’s have 2 domains, The Catalytic domain is where what happens?
autophosphorylation
Gprotein receptors have ___#__ pass membrane receptors?
7
Downstream signaling molecules bind Inside or outside of the Catalytic domain?
Outside. Inside the catalytic domain is where the tyrosine kinases are phosphorylating eachother, (ie within the dimer intracellularly)
Downstream signaling molecules have domains that bind to specific phosphotyrosine-containing peptides at domains called _________?
SH2 domains
name 3 residues on protein kinases that recieve signal/phosphorylation, and take part in autophosphorylation.
Y, T, S
What are the two roles of autophosphorylation?
•Phosphorylation of tyrosine in the catalytic domain
increases protein kinase activity.
•Phosphorylation of tyrosine outside the catalytic domain creates binding sites for other proteins that transmit
signals downstream of the activated receptors
When are receptor tyrosine kinases unphosphorylated and monomeric?
In the absence of Ligand.
T/F and why/whynot?
Cytokine receptors and Tyrosine kinase Receptors can autophosphorylate.
False. Cytokine receptors, cannot and must employ something else to do its autophosphorylation. See that there is not Kinase in the name.
•Cytosolic domains of cytokine receptors are associated with kinases such as _____ that do all the dirty work of autophosphorylation.
Jak
Jak binds the SH2 site of what signal Tranducer?
STAT (signal Transducer Activator of Transcription)
In the camp pathway ATP is converted to _______?
cAMP
Which G protein Subunit activates Adenyl cyclase?
alpha
cAMP is degraded to AMP by what enzyme?
phosphodiesterase
cAMP binds to cAMP dependent ________ _________. Its Activated catalytic subunit is released and translocates to the ________.
protein kinase (kinase A) nucleus
In the cAMP pathway, ultimately to expression genes… the Catalytic subunit of protein kinase A binds to _______ (transcription factor)which is bound to ______ (regulatory sequence).
CREB (CRE Binding prot)
CRE (cAMP response element)
Of the pathways, which is know for a Direct and rapid way of turning on a set of genes?
JAK-STAT pathway
Of the following in the Jak-STAT pathway, which form Dimers?
Cytokine Receptors, JAK, STAT, CREB
Cytokine receptors and STAT for dimers.
JAK gets close enough to Phosphorylate eachother and the receptors, but do not bind. CREB is in cAMP pathway.
How many Phosphorylations are there in the ERK-MAP kinase Pathway? and what are the kinases that do this?
3 Phosphorylations by 3 different protein kinases
RAF (MAP3K)
MEK
ERK (MAPK)
Of the 3 different protein kinases in the ERK-MAP pathway,
Which are associated with Ser-Thr and which with Try-Thr prot. kinases?
RAF (MAP3K) Ser-Thr prot. kinases
MEK Try-Thr prot. kinases
ERK (MAPK) Ser-Thr prot. kinases
RAF (MAP3K)
MEK
ERK (MAPK)
•Activated MAPK translocates into nucleus and phosphorylates _________?(transcription factor).
Elk-1
In the ERK-MAP Kinase pathway, intially in the cell, 2 proteins bind to begin the signal pathway. Also, at the very end of the pathway, 2 proteins are bound by ELK-1 to begin transcription. name the 2 protein bound pairs at both ends of the pathway?
RAS - RAF
SRE- SRF
(main thing to know for this pathway) The PIP2 pathway is another secondary messenger that uses autophosphorylation which lead ultimately to gene expression by transcription factors. BUT this is also know for one other special action, the release and mobilization of ___ from the ______ ____?
Ca2+ from the Smooth ER.
Their are 5 main players in the PIP2 pathway, that he told us to review the diagram on, but didn’t cover in class? Do you happen to know those players
PLC-gamma –>
PIP2 converted to DAG and IP3 by PLC-gamma
DAG (activates PKC) & IP3 (mobilizes Ca2+)
Protein Kinase C
Be able to list the major examples of signaling mechanisms.
Receptor Tyrosine Kinases Cytokine Receptors (most simplistic) cAMP Pathway ERK- MAP pathway PIP2 pathway (also Ca2+ mobilization)
Describe each of the major examples of cell signaling mechanisms: endocrine, paracrine, autocrine, neurotransmitter, and neuroendocrine.
over a distance through blood Nearby self synapses Posterior pituitary
Be able to list and describe the mechanism of action of cell signaling molecules: receptor-G-protein-effector, enzyme-linked, steroid messengers, and gasses as
messengers
yes you
