Exam 3 Part 5 Flashcards
switches
used in most signaling from the surface
can switch on with the addition or removal of phosphate or GTP
protein kinase
phosphorylates ATP to ADP
protein phosphatase
removes phosphate from something like a switch
G-proteins
ex. Heterotrimeric GTPase
big, 3 unit protein involved in signalling
Heterotrimeric GTPase
has alpha, beta, and gamma subunits
Signal binding to a 7 transmembrane domain receptor causes the complex to bind to the receptor, and alpha subunit disassociates
Second messengers
amplify a signal
ex. cyclic AMP, adenylyl, inositol triphosphate, DAG, Ca++
Second messengers
amplify a signal
ex. cyclic AMP
investingating singaling
cell functional data (migration, aggregation, cell death, cell growth, etc)
western blot
look for changes in protein expression in response to signaling
antibodies for signaling events
co-immunoprecipitations
DNA arrays
measure gene transcriptions
microarray
compares two populations of expressed genes to see what differing cell conditions does to expression
uses a disc where samples will hybridize to nucleotides in certain wells
cell transfection
addition of extra-chromosomal DNA to a cell
transient transfection
have genes NOT pass onto next gen
new genes do NOT become part of the genome
stable transfection
genes become part of the gemone and pass to nxt gen
stable transfection
genes become part of the genome and pass to nxt gen
mutational analysis
can introduce a mutant gene that is always on or offf. ex. look at enzyme-linked receptors and change a binding site to something else that does not phosphorylate OR change to perpectually phosphorylated with glutamate
glutamate
has a group that looks like phosphate – can be used to see what a perpetual phosphorylation does
FRET
fluorescence resonance energy transfer
uses wavelengths to excite proteins to see if they are looked near each other in 3D space
enzyme-linked receptors
receptor has an enzyme domain which becomes enzymatically active upon binding to a receptor
2 individual proteins move together upon binding to become active together – phosphorylate each other (autophosphorylation)
phosphates serve as docking sites for other proteins to come together
autophosphorylation
2 enzymes in enzyme-linked receptors phosphorylate each other
these phosphates serve as docking sites for other proteins
amino acids with OH group
serine, threonine (similar side chains), and tyrosine
RTK
receptor tyrosine kinase
on enzyme-linked receptors
small GTPases
individual alpha subunit that exists by itself
couple with enzyme-linked receptors
most important aspect of cell signaling
there is an altered cell behavior
matrix and signaling
matrix can be a signaling ligand (thus, integrins can be signal receptors)
loss of adhesion can lead to cell death
stretching of cells changes intracellular signaling
organ growth depends on matrix
stem cells rely on matrix rigidity for differentiation
Vibrio cholerae
prevens the alpha subunit from shutting off, leading to high secretion of water and salt
Bordetella pertussis
prevents the activation of the alpha subunit, turning off cAMP production
