Cell Signaling

Local Signaling

direct contact, uses gap junctions

Example of Local Signaling

nerve signals, growth factors

One instance of Long distance signaling

hormones travel through the bloodstream, the receptor on the cell has to match the hormone to respond to signal

How does Bacterial Signaling work?

Quarum sensing tells how many bacteria are present to target attack

Steps of Signaling

Reception, Transduction, Response

Signal Reception

Ligand molecule binds to a receptor protein

Transduction

protein changes shape to carry signal inside

Response

the cell is going to do something

3 main types of Receptors

GPCR, RTK’s, ion channel receptor

GPCR

a ligand binds which activates the G protein. The G protein activates an enzyme to trigger response.

the 2 ligands of the RTK produce how many cell responses?

2

How much ATP is required to activate the Tyr?

6

How does RTK create a cellular response?

The 2 relay molecules

How does the ion channel open?

1 ligand molecule binds to the ion channel

What happens when the ion channel opens?

The specific ion is allowed in

Intracellular

within the cell

Intercellular

between cells

Intracellular Receptor

receptor proteins found on the inside of the cell

The ligands of intracellular receptors are…?

small and hydrophobic in order to cross the cell membrane

What does transduction utilize?

2nd messengers to relay the response

Transduction includes..?

Phosphorylation Cascade, cAMP, Calcium Ions

Phosphorylation Cascade

Causes a change in shape due to the protein kinases

Protein Kinases

enzymes that transfer Phosphate groups

cyclic AMP (cAMP)

amplifies cell response

what dose cAMP trigger?

a Protein Kinase to phosphorylate a protein

Calcium Ions have..?

A low concentration inside the cell; it can easily cause changes

Where are large calcium stores?

Mitochondria and endoplasmic reticulum.

Ca2+ is used more widely as..?

A second messenger

The release of calcium involves…?

IP3 and DAG

What’s an example of what Cell Signaling can lead to?

Regulation of transcription or cytoplasmic activities

Where does the Response occur?

In the nucleus or cytoplasm

What do many signaling pathways regulate?

Enzyme synthesis or other proteins

What sponsors nuclear and cytoplasmic responses?

Signal Receptors, Relay Molecules, and second messengers

Aspects of Regulating Response

Amplification of signal, Specificity, Efficiency of Scaffolding proteins, Termination of Signal