DEFINITION
Cadherins are a class of transmembrane proteins. They play important roles in cell adhesion whereby they ensure cells within tissues are bound together. They are dependent on calcium ions (Ca2+) to function, hence their name.
The cadherin superfamily includes:
- cadherins
- protocadherins
- desmogleins
- desmocollins
Classical cadherins have an extracellular part consisting of five distinct Ca2+ binding domains ( cadherin repeats ) and a conserved cytoplasmic domain. The extracellular part interacts homotypically with cadherins of the neighbouring cells, and the conserved cytoplasmic tail associates with intracellular proteins ( catenin ) involved in the formation of the junctional structure.
The function of cadherins is not only limited to formation of protein complexes inside the cells and linkage of the cells together, but they also regulate the signalling events during differentiation, proliferation and migration.
THE GENES
Type I classical cadherins
Types
- E-cadherin - epithelial (CDH1)
- N-cadherin - neuronal (CDH2)
- P-cadherin - placental (CDH3)
- cadherin-4 - brain (CDH4)
- M-cadherin - muscle (CD15)
Type II classical cadherins
- VE-cadherin - endothelial cells (CDH5)
CHEMICAL STRUCTURE AND IMAGES
When relevant for the function
- Primary structure
- Secondary structure
- Tertiary structure
- Quaternary structure
Protein Aminoacids Percentage
The Protein Aminoacids Percentage gives useful information on the local environment and the metabolic status of the cell (starvation, lack of essential AA, hypoxia)
Protein Aminoacids Percentage (Width 700 px)
SYNTHESIS AND TURNOVER
mRNA synthesis
protein synthesis
post-translational modifications
degradation
CELLULAR FUNCTIONS
cellular localization,
biological function
- Cell signaling and Ligand transport
- Structural proteins
REGULATION
DIAGNOSTIC USE
E-cadherin is a 120 kDa transmembrane cell adhesion protein. It is a interaction with E-cadherin expressed by adjacent cells. The association of E-cadherin *%{color:red}calcium-dependent protein% involved in cell-cell adhesion.
Its extracellular domain mediates homophilic cytoplasmic domain* to cytoplasmic proteins called catenins is necessary for strong cell adhesion. E-cadherin C-terminus interacts directly with b-catenin, which in turn binds a-catenin, an actin-binding protein, thud providing a link between E-cadherin and the actin cytoskeleton. This interaction is critical for the establishment of adherens junctions and also for internalin mediated entry.
At the implantation stage, E-cadherin is expressed in all cells of embryos. Later this molecule disappears from the mesoderm. Some regions of the ectoderm and all endodermal cells maintain the expression of E-cadherin, and this expression persists as long as they differentiate into epithelial cells.
E-cadherin is involved in Listeria Monocytogenes infection
N-cadherin
N-cadherin is a 140 kDa protein belonging to a family of transmembrane molecules that mediate calcium-dependent intercellular adhesion. Cadherins are involved in controlling morphogenetic movements during development and regulate cell surface adhesion through homotypic adhesion with the same cadherin species.
As cells differentiate into into mesoderm soon lose E-cadherin and come to express only N-cadherin.
Expression of N-cadherin has been reported on a variety of tissues including neuronal, endothelial and muscle cells, and a subpopulation of early hematopoietic progenitor cells.
P-cadherin
P-cadherin is present in the basal layer of the epidermis.
It is continuously distributed from the maternal tissues to the embryonic tissues giving rise to the placenta, suggesting that this molecule may serve to connect embryos to the uterus.
In contrast E-cadherin is localized only in the embryo.
Takeici
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N-cadherin-dependent neuron–neuron interaction is required for the maintenance of activity-induced dendrite growth 2010
http://flipper.diff.org/static/files/310/CAD1-4_ch1.png
