BIOL 201 - 6. Signaling Pathways

Tyrosine Kinase Receptors (RTK)

A single transmembrane domain with an extracellular ligand binding membrane and intracellular kinase domain

• ligand binding

• “cross phosphorylate” tyrosine residues

• autophosphorylation

• essential cellular processes

Mitogens

Proliferative chemicals

Kinase Cascade

A sequential activation of kinase family members where each kinase phosphorylates and activates the next kinase

• targets are often transcription factors that are activated by phosphorylation (turns on specific genes)

Ras

A small G-protein

• activation of Ras induces a “MAP kinase cascade”

Co-immunoprecipitation

A biochemical technique used to determine where two proteins interact (bind)

• targets the protein interactions and not just the single protein

Immunoprecipitation

A method that uses antibodies to separate a protein of interest from other molecules in a mixture (cell homogenate)

Input

The starting material or lysate used in an experiment

• shows that proteins of interest are expressed in the cell lysate and can be detected on an immunoblot

G-Protein Coupled Receptors

A receptor that contains seven transmembrane domains that, when activated, changes activity of membrane bound effector proteins

Second Messenger Molecules

Low molecular weight intracellular signaling molecules which changes concentration in response to receptor activation and binds to and modifies other pathway proteins

cAMP Signaling Pathways

A pathway with the goal of glycogen breakdown in response to epinephrine or glucagon binding

• enzymes involved in glycogen breakdown are activated by PKA

Adenylyl Cyclase

A membrane protein that creates cAMP

Tags

Proteins that are used as a recognition site for antibodies that in turn shows expression of a target protein

• Flag, Myc

Signal Integration

The process by which cells respond to more than one signal at a time to produce and coherent and coordinated outcome