Cadherins are expressed in both vertebrates and invertebrates. Single pass transmembrane glycoproteins that are 700-750 amino acids long. The extracellular domain is folded into 5-6 cadherin repeats with Ca2+ ions binding in between the repeats making them a stiff rod-like structure
E-cadherin – found in epithelium and parts of brain
N-cadherin – found on neurons, muscle and lens cells, fibroblasts
P-cadherin – found in placenta and epidermis
T-cadherin – found on neurons and muscle cells
Cadherins play a role in vertebrate development. Initially, the ectoderm cells express E-cadherin. When neural tube cells break away from the ectoderm, they begin to express N-cadherins. The neural crest cells breaking away from the neural tube cells express another type called cadherin -7 that holds them together. Finally, when the cells aggregate to form a ganglion, they re-express N-cadherin.
Protocadherins – found on synapse of neurons
VE cadherin – Receptor tyrosine kinase co-receptor. Not only mediates adhesion between endothelial cells but also transmit extracellular signals to the cell interior
Selectins are lectins (carbohydrate binding proteins). Ca2+ dependent CAMs
L-lectins – on WBCs
P-lectins – on platelets
E-lectins – on activated endothelial cells
Ca2+ independent CAMs belong to Ig (immunoglobin) superfamily
N-CAMs (neural cell adhesion molecule) – On neurons and many other cell types. Some types of N-CAMs in neurons associates with Src family cytoplasmic tyrosine kinase helping signals to be mediated intracellularly by phosphorylating intracellular proteins
ICAMs (Intercellular adhesion molecules) – On endothelial cells. Bind to integrins on blood cells aiding migration out of blood vessels
FAS 3 (fasciclin III) – Expressed on some motor neurons and the muscle cells they innervate
How Selectins And Integrins Mediate Cell-Cell Adhesion For WBC To Move Out Of The Bloodstream Into Tissue
