exam 2 - cell communication

communication

________ between cells and the environment is critical to function of life

intracellular signaling

communication within a cell

intercellular signaling

communication between cells

ligands

small molecules that serve as chemical signals

receptors

interact with ligands and receive them in target cells

autocrine

fast form of cell signaling where a cell targets itself

gap junctions

fastest form of cell signaling where small molecules/ions diffuse via cytoplasm

paracrine

fast form of chemical signaling where a cell targets a nearby cell

endocrine

slowest form of cell signaling where a cell targets a distant cell through the bloodstream

non-polar ligands

diffuse through plasma membrane and interact with intracellular receptors (steroid hormones, vitamin D, nitric oxide)

polar ligands

bind to extracellular domain of cell-surface receptors (peptides and proteins)

intracellular receptors

found in the cytoplasm or nucleus and respond to ligands that diffuse through plasma membrane

cell-surface receptors

found on plasma membrane and help convert extracellular signals into intracellular responses

ligand-gated ion channel, g protein-coupled receptor, receptor tyrosine kinase

three types of cell-surface receptors

ligand-gated ion channel

type of cell-surface receptor important in neuronal synaptic transmission; ligands are neurotransmitters and when bound open up ion channels

g protein-coupled receptor

largest family of cell-surface receptors in humans; GPCR is coupled with a G-protein that can bind GDP or GTP

a, b, y

three subunits of G proteins

receptor tyrosine kinase

type of cell-surface receptor that has enzymatic activity and involved in cell growth, division, survival

cortisol receptor

intracellular receptor that functions as a ligand-activated transcription factor

chaperone proteins

keep the receptor in the correct folded shape and prevent it from entering the nucleus prematurely

signal reception

specific interaction between ligand and receptor that leads to a conformation change

signal transduction

intermediate steps that often involve activation/inactivation of enzymes and can include secondary messengers; ultimately leads to cellular response

second messengers

activated by the initial messenger and carries instruction through the cell

cyclic AMP (cAMP)

can activate downstream protein kinase A

amplification

small signal leads to a large response

protein kinase

addition of a phosphate group to a protein (phosphorylation)

protein phosphatase

removal of a phosphate group from a protein (dephosphorylation)

adenylyl cyclase

formation of cyclic AMP (cAMP) from ATP

phosphodiesterase

formation of AMP from cyclic AMP (cAMP)