16 Cell Signaling- Cell Bio

Endocrine Signaling

signal molecules like hormones are secreted by endocrine cells into the bloodstream

long range signaling

Paracrine Signaling

signal molecules diffuse in the extracellular fluid and act as local mediators to target cells

fast

Autocrine Signaling

secreting cell responds/self-signaling

Neuronal signaling

signal molecules as neurotransmitters are delivered to a specific target cell at the synapse

What is the difference between neuronal and paracrine signaling?

Both fast but neuronal is specific

Contact-dependent signaling

signaling and target cells are in direct physical contact

signal molecule not released, interacts with receptor in target cell

Which type of receptors do steroid hormones act on?

intracellular receptors since they are small and can cross the cell membraneF

Fast cell response

change in protein activity

Slow cell response

change in gene expression, cell growth, and division

Examples of hormones that cross the plasma membrane and bind intracellularly

steroid, thyroid (cortisol, estradiol, testosterone)

Is NO release from endothelial cells a fast or slow response?

fast

Does protein kinase turn a signal on or off? (ATP to ADP or reverse?)

turns it on (turns to ATP)

Does protein phosphatase turn a signal on or off?

Off (phosphorylates losing P and turning signal off)

Does GTP binding turn a signal on or off?

turns it on, GDP leaves, GTP binds

Does GTP hydrolysis turn a signal on or off?

Off, loses P turning into GDP

What does GEF (Guanine nucleotide exchange factor) do?

activated G protein promoting the binding of GTP

What does GAP (GTPase-activating protein) do?

inhibits G-protein, hydrolyzing it to GDP

Ion channel-coupled receptor

opens in response to binding an extracellular signal molecule (transmitter-gated ion channel)

What signal do ion-channel-coupled receptors convert into?

chemical to electrical signals

G protein-coupled receptor

signal molecule binding to a GPCR activated a G-protein