Bio 111 lecture 19

what do the ‘talking cells’ put out in cell communication?

ligands(signal molecules)

what to the ‘listening cells’ have in cell communication?

receptors for the ligands to attach to

what do ligand/receptor complexes do?

transduce/transmit a signal into the cell(signal transduction)

what does signal transduction lead to?

a cellular response

what are these examples of?

altered metabolism, altered gene expression, altered cell shape or motility

cellular responses

how many categories of cell signaling are there?

five

what are the categories of cell signaling based on?

distance between the cells that are communicating

type of cells that are communicating

what is autocrine signaling?

cell signaling to itself

what type of signaling are these examples of?

immune cells and cancer cells

autocrine

what is direct contact?

cell to cell surface transmission of ligands through receptors or gap junctions

what type of signaling are these examples of?

embryonic development and wound healing

direct contact

what is paracrine signaling?

cells signaling to nearby cells

what type of signaling is this an example of?

development of the spinal cord during embryonic development

paracrine signaling

what is endocrine signaling?

systemic(organism wide) signaling via the circulatory system

what type of signaling are these examples of?

hormones

endocrine signaling

what is synaptic signaling?

signaling by a nerve cell through a synapse to another cell

what type of signaling are these examples of?

neuromuscular junctions

synaptic signaling

can hydrophobic or hydrophilic ligands diffuse across the plasma membrane?

hydrophobic

what do hydrophobic ligands bind to?

intracellular receptors

what do hydrophilic ligands bind to?

membrane bound receptors

what are ion channel receptors?

a type of membrane bound receptor

ligand binding opens the ion channel across the membrane

what is an enzymatic/catalytic receptor?

a type of membrane bound receptor

ligand binding activates the enzymatic activity of the intracellular signaling domain

what are G protein-coupled receptors(GCPRs)?

a type of membrane bound receptor

activation of a target protein through G protein complexes

what are g proteins made of?

alpha, beta, and gamma subunits

are GDP-bound or GTP-bound G proteins active?

GTP-bound

are GDP-bound or GTP-bound G proteins inactive?

GDP-bound

how do G proteins become inactivated?

the alpha protein subunit hydrolyzes GTP, converting it into GDP