bio chapter 9: cell communication

types of signaling

autocrine (self-signaling),

paracrine (nearby cells),

endocrine (long-distance via bloodstream),

juxtacrine (direct contact),

gap junctions (direct cytoplasmic connection)

Membrane vs Intracellular receptors

Membrane (hydrophilic ligands)

- ion gated channel

- protein kinase

- GCPR

Intracellular (hydrophobic ligands)

- intracellular

kinases vs phosphatases

-Kinases transfer phosphoryl from ATP to seryl/threonyl or tyrosyl on enzyme to increase/decrease activity

-Phosphatases remove a phosphoryl group from an enzyme

tyrosine kinase

An enzyme that catalyzes the transfer of phosphate groups from ATP to the amino acid tyrosine on a substrate protein.

MAP kinase

Mitogen-activated protein kinase. Signaling molecule that is the final kinase in a three-kinase sequence called the MAP-kinase signaling module.

G protein-coupled receptors (GPCRs)

a large family of proteins that function as receptors; they provide a mechanism for molecules outside a cell to influence the inner workings of the cell

function of coactivators

catalyze the addition of acetyl groups to lysine residues in the tails of histone proteins.

ligand

A molecule that binds specifically to another molecule, usually a larger one

-hormones, neurotransmitters, growth factors

second messenger

A small, nonprotein, water-soluble molecule or ion, such as calcium ion or cyclic AMP, that relays a signal to a cell's interior in response to a signal received by a signal receptor protein.

signaling cascade vs scaffolding protein

Signaling cascades are sequential, enzymatic, and biochemical pathways (e.g., phosphorylation) that transmit signals across a cell, while scaffolding proteins are structural, non-catalytic proteins that physically bind and organize these cascade components to improve efficiency and specificity. The cascade carries the message; the scaffold ensures the message reaches its destination