Cell communication
Direct communication
Desmosome
Joins
Gap junction
Communicates
Tight Junction
Prevents
- Forms belt around cell, anchoring it to neighboring cells
- Not attached to cytoskeleton
- Belt stops membrane proteins moving past it
& stops diffusing molecules
- Anchor cells together
- Attached to cytoskeleton
- Cadherins form links between plaques of individual cells
- Channels or bridges between cells: connexins
- Allow small molecules + ions to pass between cells
- Small chemical and electrical signals e.g.
- Electrical signal smooth muscle
Chemical communication
Neural
Ach: skeletal muscle
Nor-adrenaline: vasoconstriction
Glutamate:CNS
GPCR
G proteins
Gq: activate phospholipase C
Gs: stimulates adenylate cyclase
Gi: Inhibits adenylate cyclase
Tyrosine kinase
Ligand binds: tyrosine molecules become phosphorylated
other intracellular proteins then bind to tyrosine kinase and are activated
Transmembrane protein normally inactive