Introduction to Signal Transduction - AP Biology

Paracrine signaling. Local signaling between nearby cells via diffusion.

Inositol triphosphate (IP3). Second messenger that triggers calcium release from ER.

To transmit signals from cytokines to the nucleus. Cytokine-activated pathway directly phosphorylating transcription factors.

GTP. High-energy nucleotide activates the alpha subunit for signaling.

Hydrolysis of GTP to GDP by the alpha subunit (GTPase activity). Built-in enzyme activity returns G protein to inactive state.

Pathway activation occurs even without ligand binding. Always-active receptor signals continuously regardless of ligand presence.

It binds calcium and activates various proteins. Calcium-binding protein that activates target enzymes.

Signal reception by a receptor protein. First step where signaling molecule binds to receptor.

Juxtacrine signaling. Cell-to-cell contact signaling via membrane-bound molecules.

They remove phosphate groups from proteins. Reverse kinase action by dephosphorylating proteins.

Endocrine signaling. Long-distance signaling via circulatory system transport.

Specificity and regulation of cellular responses. Ensures appropriate cellular responses to external stimuli.

To transfer phosphate groups to tyrosine residues. Autophosphorylation activates kinase domain for downstream signaling.

To regulate gene expression and cell division. Phosphorylation cascade controlling cell growth and differentiation.

Paracrine signaling. Local signaling between nearby cells via diffusion.

Receptor tyrosine kinases. Dual-function proteins with catalytic activity when activated.

To convert an external signal into a cellular response. Converts extracellular stimuli into intracellular responses.

A molecule that binds specifically to a receptor. Signal molecule with specific receptor binding affinity.

To regulate and maintain cellular responses. Prevents excessive signaling by inhibiting pathway components.

Activation of a G-protein. Conformational change activates the G-protein signaling cascade.

Steroid hormone receptors. Lipophilic hormones cross membrane to bind inside cell.

It converts ATP to cAMP. G-protein activated enzyme producing cAMP second messenger.

Growth factors. Molecules that stimulate the same cell that secreted them.

In the nucleus after receptor binding. Steroid-receptor complexes directly regulate transcription.

To relay signals from receptor tyrosine kinases. GTPase that activates MAP kinase cascades downstream.

It regulates various cellular processes. Controls muscle contraction, enzyme activity, and gene expression.

To open or close in response to a ligand binding. Channel conformational change allows ion permeability.

Small molecules that relay signals inside the cell. Intracellular messengers that amplify receptor signals.

It activates receptor tyrosine kinases. Two receptors pair to activate their kinase domains.