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Intro
ex3 - signals
10
Medical
Professional
09/26/2011

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Term
enzyme-linked receptors
Definition

NOT serpentine, NOT G-proteins

 

have enzymatic activity, i.e. guanyl cyclases which binds ANP and is membrane bound or the cytosolic one which binds NO 

Term
nitric oxide
Definition

(only gas currently known to work as a signalling molecule)

 

cannot accumulate bc breaks down easy

 

comes from arginine.  one inducible NO synthase (NOSi) is activated by Ca2+

 

can act of cell in which it was produced to diffuse out of cell.  therefore, an intracellular second messenger or a paracrine first messenger

Term
cGMP?
Definition

the product of NO activation of guanyl cyclase

 

cGMP causes vasodialation (important for the action of viagra, i believe)

Term
production of NO by nitroglycerine
Definition

nitroglyc can break down to form NO

 

NO can relax arterioles from here, and this causes relief from angina pectoris

Term
two types of kinases?
Definition
those that work with tyrosine only, or those working with serine and threonine only
Term
the actions of a kinase
Definition
tyrosine kinase, specifically, can bind a growth factor, this causes a signalling cascade in which the tails of the kinase phos each other (dimerize) @ specific residues (are now stimulated).  all those PO4 can then serve as the sites for many other signaling proteins to bind.  Tyr kinases kick of the signaling of many downstream pathways
Term
a few important cascades kicked off by tyr kinases?
Definition

Ras: this pathway works as to activate transcription factors. the final proteins of ras cascades that are activated are proto-oncogenes and transcription factors.  ras needs an ADAPTOR protein and ACTIVATING protein to be activated

 

Src: basically same as Ras.  Also very prevalent in cancer

 

monomeric g proteins:  ras is a member of these.  have the same GTP hydrolyzing abilities, but are structurally different

- ras promotes growth, rab and rho/rac promote other fxns

Term
more of Ras, how does a typical cascade work?
Definition
Ras activates MAP (mitogen activated protein ) kinase-kinase-kinase, which activates MAP-kinase-kinase, which activates MAP kinase, which activates an number of growth/transcription factors
Term
how do intracellular/nuclear receptors work?
Definition

they can be in the cytosol or the nucleus.   if they are in the cytosol, then they will have to be transported to the nucleus after they bind their receptor.

 

these are both TRANSCRIPTION FACTORS.

 

receptors include things like, hormones, vitamins, retinoids, T3, T4

Term

which one of these can bind a heat-shock protein?

 

steroid,

T3,

T4,

Vetinoid

Vitamin D

Definition
steroids - also has the unique abilty to bind different types of gene styles (ie. early regulatory genes and structural genes)
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