Cell junctions, adhesion and ECM

Cell junctions, adhesion and ECM

1. Cell junctions

   • Anchoring proteins
     • Cell to cell: cadherins Cell to matrix: integrin
       • Actin filament
         • C-C: Adherens j.
         • C-M: actin-linked c.m. adhesions
       • Intermediate filament
         • C-C: Desomsomes
         • C-M: Hemidesmosomes
   • Occluding proteins
     • Claudins
       • Tight/septate junctions
       • Occludins
   • Channel-forming proteins
     • Connexin/innexin
       • Gap junctions, Plasmodesmata
   • Signal-relaying proteins
     • Anchorage- and signal-relaying proteins
   • Example:
     • Cell 1
       • Actin filaments
         • Catenin
           • Cadherin x2
             • Flexible hinge region function dependent on Ca2+
     • Cell 2
       • Actin filaments
         • Catenin

2. Selectins

   • Transmembranal carb-binding protein
   • L-selectin: leukocytes; P-selectin: platelets; E-selectin: epitheleum
   • Heterophilic: bind to specific oligosaccharides and glycoproteins

3. Integrins

   • Enforce blood cell adhesion (proteins)
   • Binds also to:
     • VCAM's: Vascular cell adhesion molecules
       • Which belong to the:
     • ICAM's: Intercellular cell adhesion molecules

4. Immunoglobulin superfamily

   • NCAM; Neuron cell adhesion molecules; synapses; scaffold with many types of adhesion molecules