Local Signaling

(2 Types)

Means of cell communication; two types .. Paracrine (organ) and Synaptic (nerve) Signaling

Both use ligands and respective receptor proteins found on the target cell

Membrane recpetor protein whose ligands are typically growth factors....composed of two monomers and when ligands bind responds with monomers dimerizing and autophosphorylation.

All tyrosine sites are phosphorylated which in turn causes other proteins to phosphorylate=physical change

involves the G-linked receptor protein;

when ligand binds, the GDP is dropped from the G protein and the GTP binds. The G protein then diffuses through the membrane to activating adenylate cyclase which converts ATP to cAMP. Protein kinase is then instructed to respond, resulting in celluar response

enzyme that converts ATP to cAMP (Cylic AMP)

specific proteins with a receptor

A receptor protein inside the target cell detects and responds to signaling molecule (LIGAND)

Once ligand bonds, the protein changes in shape thus transmitting information

G-protein coupled receptor

Tyrosine Kinase

Ion Channel

found in cytoplasm or nucleus of the targets cells

this chemical messenger passes through the cell's plasma membrane

control which genes are turned on/off

(which genes are transcribed into mRNA)

SIGNALS ARE RELAYED

Signal Transduction Pathway

relay molecules pass on information through signal transduction/shape change (phosphorylation)

Protein Phosphorylation/

Dephosphorylation

adds a phosphate

transfers phosphate from ATP to protein

RESPONSE

cell signaling leads to regulation of transcription of cytoplamsic activities

AMPLIFICATION

SPECIFY

SCAFFOLDING

multistepped transduction pathway

series of phosphorylation via kinase

Calcium Ion

Secondary Messenger

requires calcium pump during transduction;

pumps the Ca out of cell and into Endoplasmic Reticulum causing cell to respond (usually in the form of muscle contraction)

when completed, Ca is pumped out