Cell Signaling Part 1 Flashcards
allows bacteria to coordinate their behavior, including their motility, antibiotic production, spore formation, and sexual conjugation
Quorom sensing
signals cells of the opposite mating type to stop proliferating and prepare to mate.
Mating factor in yeast
Intracellular signaling pathway
Extracellular signal molecule -> receptor protein -> Intracelullar signaling molecules -> effector proteins
- Where reception of the signals depends on
- at the cell surface, which bind the signal molecules
Receptor protein
Results after the binding of the receptor
intracellular signaling pathways or system
process the signal inside the receiving cell.
distribute them to appropriate intracelullar targets
Intracellular signaling proteins
small chemical messenger which carry the signal to other signaling proteins
Second messengers
the targets that lie at the end of signaling pathways
effector proteins
Four forms of intercellular signaling
- Contact-dependent
- paracrine
- synaptic
- endocrine
requires cells to be in direct membrane- membrane contact
Contact-dependent signaling
depends on local mediators that are released into the extracellular space and act on neighboring cells.
Paracrine signaling
is performed by neurons that transmit signals electrically along their axons and release neurotransmitters at chemical synapses, which are often located far away from the neuronal cell body
Synaptic signaling
depends on endocrine cells, which secrete hormones into the bloodstream for distribution throughout the body
Endocrine signaling
cells produce signals that they themselves respond to
Autocrine signaling
neurons; chemical
synapses
synaptic
high specificity of binding site of receptors
Target cell
extracellular signal molecule
ligand
cell responds to the signals ___
selectively
a signal molecule often has ___ ___ on different types of target cells
different effects
Acetylcholine effect in heart pacemaker cells
decreases the rate of action potential firing
Acetylcholine effects in salivary gland cells
stimulates the production of salive
Acetylcholine effets in skeletal muscle
causes the cells to contract
Cell surface receptors act as __ __
signal transducers
Three major classes of cell-surface receptor proteins
- Ion-channel-coupled receptors
- G-protein coupled receptors
- Enzyme-coupled receptors
- rapid synaptic signaling between nerve cells and other electrically excitable cells
- transmitter-gated ion channels or ionotrophic receptors
- electrically excitable cells
- Ion-channel-coupled receptors
- act by indirectly regulating the activity of a separate plasma-membrane-bound target protein (enzyme or ion channel)
- G-protein coupled receptors
mediates the interaction between the activated receptor and this target protein
heterotrimeric GTP-binding protein
function as enzymes or associated directly with enzymes
- Enzyme-coupled receptors
covalently adds one or more phosphate groups to specific amino acids on the signaling protein
Protein kinase
removes the phosphate groups
protein phosphate
Two Types of interacellular signaling proteins that act as molecular switches
- Signaling by Phosphorylation
- Signaling by GTP binding
Signaling by phosphorylation
- A protein kinase covalently adds phosphate from ATP to signaling protein
- A protein phosphate removes the phosphate
Signaling by GTP binding
- GTP binding protein was induced to echcnage GDP to GTP
- Activates the protein
- The protein then inactivates itself by hydrolizing GTP to GDP
When GTP is bound it is an ___
on state