Signal Transduction

Front 1

Primary Messenger

Back 1

Signal that initiates the pathway; comes to the outside of the cells

Front 2

Ligand

Back 2

A primary Messenger molecule

Front 3

Second Messenger

Back 3

Used to relay information from receptor-ligand complexes

Front 4

Cross talk

Back 4

Competing Inputs from several different signal pathways

Front 5

B-Adrengurgic Receptor

Back 5

A 7TM receptor that intercepts epinephrine.

Front 6

7TM Receptor

Back 6

A broad class of cell-surface receptors that have 7 helical domains that lie in the cell membrane.

Front 7

Rhodopsin

Back 7

A protein in the retina of the eye that senses the presence of photons and initiates the signal cascade responsible for vision.

Front 8

G-Protein

Back 8

Binds guanyl nucleotides; the active (GTP) form stimulates adenylate cyclase.

Front 9

G-protein coupled Receptor

Back 9

Receptors that transduce the ligand's information first through a G-protein.

Front 10

Adenylate Cyclase

Back 10

Produces cAMP from ATP. It is a membrane protein; activated by active G-proteins.

Front 11

Protein Kinase A

Back 11

cAMP-activated Kinase that phosphorylates a variety of proteins. Responsible for most of the effects of cAMP in Eukaryotic cells. PKA also stimulates the expression of certain genes by phosphorylation genes a transcriptional activator.

Front 12

B-Adrenergic Receptor Kinase

Back 12

Deactivates the B-Adrenergic Receptor as a form of pathway regulation.

Front 13

Phosphatidylinositol 4,5-bisphosphate (PIP2)

Back 13

A phospholipid present in the cell membrane; its cleavage is the first step in many signaling pathways.

Front 14

Phospholipase C

Back 14

G-protein activated enzyme that breaks PIP2 into two second messengers.

Front 15

Protein Kinase C

Back 15

Phosphorylates serine and threonine residues in many target proteins. Modulated IP3 and Ca2+.

Front 16

Calmodulin

Back 16

A calcium-binding protein that acts as a clamp to induce structural changes in several different proteins. An especially noteworthy target are calmodulin-dependent kinases (CaM Kinases).

Front 17

EF Hand

Back 17

A helical motif in CaM that binds calcium ions.

Front 18

CaM Kinase

Back 18

Calmodulin-dependent Kinase that helps regulate fuel metabolism, ionic permeability, and neurotransmitter synthesis and release.

Front 19

Insulin

Back 19

A peptide hormone that consists of two chains linked by three dipeptides.

Front 20

Insulin Receptor

Back 20

Intercepts the ligand insulin; contains a tyrosine kinase. Insulin binding results in the cross-phosphorylation and activation of this Kinase.

Front 21

Tyrosine Kinase

Back 21

Catalyzes the transfer of a phosphoryl group to the OH on a Tyrosine residue.

Front 22

Receptor Tyrosine Kinase

Back 22

A receptor-bound Tyrosine Kinase, such as the one found on the insulin receptor.

Front 23

Insulin receptor substrates

Back 23

Phosphorylated sites on insulin receptors serve as docking sites for other substrates; these are called insulin receptor substrates.

Front 24

Adaptor Protein

Back 24

Nonenzyme molecules that can serve to tether the downstream components of a signal pathway to the membrane.

Front 25

Src Homology 2 Domain

Back 25

Recognize phosphotyrosine sequences; these domains are present in many signal-transduction proteins. Each specific SH2 shows a binding preference for phosphotyrosine in a particular sequence context.

Front 26

Epidermal Growth Factor

Back 26

A signal factor. The initiator is a tyrosine kinase. Stimulates the growth of epidermal and epithelial cells.

Front 27

Dimerization Arm

Back 27

A piece of each monomer that reaches out and binds other monomers. Thi serves to activate the protein.

Front 28

Ras

Back 28

A small G-protein that is part of the EGF-transduction pathway. Sos opens a channel in RAS that allows GTP to enter.

Front 29

Small G Protein

Back 29

Play a prominent role in signal-transduction pathways. These proteins are activated by GTP.

Front 30

Guanine Nucleotide Exchange Factor (GEF)

Back 30

A molecule, such as sos, that enables GTP to be exchanged for GDP in a G-protein.

Front 31

Extracellular signal-regulated kinase

Back 31

A kinase that phosphorylates many different targets, including some gene regulation molecules.

Front 32

GTPase-activating protein

Back 32

Proteins that help regulate signal transduction by activating GTP hydrolysis into GDP; puts a limit on the lifetime of activated G-proteins.

Front 33

Oncogene

Back 33

A gene that leads to the generation of cancerlike characteristics in succeptible cells.

Front 34

Proto-Oncogene

Back 34

A gene that, when mutated, can be converted into an oncogene.

Front 35

Tumor-suppressor gene

Back 35

A gene that helps stop cell growth; if both copies are gone than cancerous growth can occur. This insludes some phosphatases.