C16 Cell Communication Flashcards
Four types of signals
endocrine, paracrine, neuronal, contact-dependent
endocrine
secretes hormones into bloodstream
paracrine
signal induces changes in nearby cells
Steroid hormones are a type of ? receptors
intracellular
cortisol pathway
cortisol readily flows into cell, binds to nuclear receptor protein and induces conformation change to activate it. complex moves into nucleus and binds to regulatory region of target gene to activate
two typers of molecular switches
signaling by phosphorylation (activates kinase). signaling by GTP-binding protein.
Activated G protein subunits
alpha and beta-gamma complex
Three types of cell-surface receptors
ion-channel-linked, g-protein-linked, enzyme-linked
Nitric oxide
diffusible signalling molecule. Activated NO synthase produces NO from arginine and causes relaxation of smooth muscle
G-proteins can activate ? and ? proteins
ion channel and enzymes
adenylyl cyclase is activated by a G-protein linked receptor to make ?
cAMP
serotonin increases ? in nerve cell
cAMP
Fertilization of an egg triggers wave of ? that initiates development
Ca++
largest class of enzyme linked receptors
tyrosine kinases
tyrosine kinases
signal activates kinase, autophosphorylating each receptor. phosphates become binding sites for other intracellular signaling proteins
constitutively active ras mutant cannot hydrolyze GTP causing
continual growth
growth stimulating factors
mitogens
MAP kinases
ras activated phosphorylation cascade that activates many other kinases. phosphorylates and activates many proteins
akt function
suppresses cell death by BAD and inhibits apoptosis by activating Bcl2
akt promotes cell growth by activating ?
kinase tor
Rapid gene activation pathways
cytokines and tgf-beta
cytokine function
activate jak/stat pathway that can rapidly activate gene expresion
tgf-beta function
girectly activate SMADs
NO pathway summary
ca++ activates no synthase. no synthase makes no from arginine. no diffuses into other cell and triggers guanylyl cyclase to make cGMP which promotes relaxation
heart muscle contraction pathway summary
acetylcholine binds to gprotein. activated betagamma complex opens ca++ channel casuing heart contraction. k+ closes with alpha ATP hydrolysis and binding to betagamma
glucose production pathway summary
adrenaline binds to gprotein. alpha subunit activates adenylyl cyclase to make cAMP. cAMP activates PKA initiating a phosphorylation cascade ultimately activating glycogen phosphorylase.
