terms and definitions Flashcards
mediate the communication between cells in multicelluar organisms
extracellular signal molecules
process the signal inside the receiving cell
intracellular signaling proteins
lie at the end of signaling pathways
effectors
important during development and in immune responses
contact-dependent signaling
act only on cells in the local environment
local mediators
four forms of intracellular signaling
contact-dependent signaling, paracrine signaling, synaptic signaling, endocrine signaling
form of signaling that requires cells to be in direct membrane contact
contact dependent
depends on local mediators that are released into the extracellular space
paracrine signaling
performed by neurons that transmit signals electrically along their axons
synaptic signaling
depends on endocrine cells which secrete hormones into the bloodstream
endocrine signaling
requires a differet combination of survival and differentiation of signals
terminal differentiation
three major casses of cell-surface receptor proteins
ion channel, GPCR, enzyme coupled receptor
transmitter-gated ion channels involved in synaptic signaling
ion channel coupled receptor
indirectly regulating the activity of a separate plasma membrane bound target protein
GPCR
single pass transmembrane proteins that have their ligand binding outside the cell and their catalytic or enzyme binding site insite
enzyme coupled receptor
generate in large amounts in response to their receptor activation
second messengers
examples of second messengers
camp, DAG, ip3
a second messenger that is water soluble and diffuse into the cytosol
camp
a second messenger that is lipid soluble and diffuse in the plane of PM
DAG
a second messenger that is water soluble and opens the ca2+ channel in the ER
ip3
two types of molecular switches
protein kinase, gtp binding protein
adds one or more phosphate groups to specific amino acids
protein kinase
two types of protein kinase
serine/threonine and tyrosine kinases
they switch between and on state when gtp is bound and an off state when gdp is bound
gtp binding proteins
bring together groups of interacting signalling proteins into signaling complexes
scaffold proteins
these are the specialized behaviors that produce a response appropriate for cell function
response timing, sensitivity, dynamic range, persistence, signal processing, integration, coordination
these are feedback loops
positive and negative feedbacks
in this feedback the output stimulates its own production and can transform the behavior of the responding cell, producing an all or none response
positive feedback
in this feedback, the output inhibits its own production
negative feedback
our senses of sight, smell and taste depend on these receptors
GPCR
three subunits of g proteins
a, b, y
an enzyme that synthesize camp from ATP
adenyl cyclase
produced by the bacterium that causes cholera and catalyzes the transfer of ADP ribose from NAD+ to the alpha subunit; found in the epithelial cells in the intestint
cholera toxin
causes pertussis, catalyzes the ADP ribosylation of th alpha subunit, preventing the protein from interacting with the receptors, found in the lungs
pertussis toxin
phosphorylates specific serines of threonines
PKA
recognize odors; the receptors are displayed on the surface of the modified cilia
olfactory receptors
in mammals, their function is to relax smooth muscle in the walls of blood vessels
nitric oxide
types of NOS
eNOS, nNOS, iNOS
NOS in epithelial cells
eNOS
NOS in nerve and muscle cells
nNOS
three general modes of adaptation
sequestration, down regulation, inactivation
largest enzyme coupled receptor
RTK
function of RAS
molecular switch, cycling between GTP and GDP
quickly reverse the phosphorylation in tyrosines
tyrosone-specific protein phosphatases
activate RAS
RAS-GEF
inactivate RAS
RAS-GAPA
THREE COMPONENTS OF MAP KINASE MODULE
MapK, MapKK, MapKKK
regulate both the actin and microtubule cytoskeletons
rho family
three character
rho, rac cdc42
PI 3-Kinase
phosphorylates inositol phospholipids and promote cell survival
cleaved by PLCb to generate IP3
PI (4,5)P2
not cleaved by PLC and remains only in the PM
PI(3,4,5)P3
produce intracellular signaling proteins bind to PI(3,4,5)P3
PH domain
major pathway activated by the hormone insulin
pi-3-kinase Akt
two serine/threonine kinases with PH domains
Akt and PDK1
receptors for some hormones; associated tyrosines kinases called janus kinases (JAKs)
cytokine receptors
activate transcription regulators called STATs
JAKs
best known for its role in the production of drosophilia neural cells
notch receptor protein
process that depends on a contact dependnet signaling mechanism that is activated by a single pass transmembrane signal protein called Delta
lateral inhibition
binds b-catenin and acts as degradation complex
protein degradation complex
four proteins of the protein degradation omplex
casein kinase 1, glycogen synthase kinase 3, axin, APC
sleep wake cycles of humans, anticipate the regular daily changes and take appropriate action in advance
circadian clocks
controls our diurnal cycles of sleeping and waking, body temperature and hormone release
SCN cells
a plant regulator responsible for stress signal in response to wounding, infection
ethylene
interacts with CTR1, dimeric
ethylene receptors
helps plans grow toward light
auxin
dimeric, cytoplasmic serine/threonine kinases which respon differentially and reversibly to red and far red light
phytochromes
sensitive to blue light and have an important role in circadian clocks
cryptochromes
