cell adhesion molecules Flashcards
What is cell adhesion molecules?
Cell adhesion molecules (CAMs) are a subset ( part ) of cell surface proteins that are involved in the binding of cells with other cells or with the extracellular matrix (ECM), in a process called cell adhesion.
what are the domain of CAMs?
- cytoplasmic/intracellular/exoskeletal domain
- Transmembrane domain
- extracellular domain
What are the way of interactions of CAMs?
- Homophilic interaction( some two CAMs )
- heterophilic interaction( CAMs bind to different type of CAMs )
- interact through linker molecule( extracellular linker molecule )
what are the families of CAMs?
- cadherin
- integrin
- selectin
- immunoglobin superfamily
briefly describe the Cadherin family of CAMs.
- glycoproteins - mediate intercellular adhesion in epithelial and endothelial cells by Ca2+ dependent homophilic adhesion
- Primarily link epithelial and muscle cells to their neighbors.
- Form desmosomes and adherens junctions of anchoring junction.
- Do not interact with the extracellular matrix.
- Also they are the most prevalent or common in vertebrates.
briefly describe the structure of the Cadherin family of CAMs.
- Contain a short transmembrane domain and a relatively long extracellular domain containing four cadherin repeats (EC1-EC4), each of which contains calcium-binding sequences.
- Cadherins interact with specific cytoplasmic proteins, e.g., catenins (α, β, and γ), as a means of being linked to the actin cytoskeleton.
- the catenins are crucial for cadherin function.
Why is catenin crucial for cadherin function?
- alpha-Catenin is required for the interaction of cadherins with the actin cytoskeleton.
- beta-Catenin participates in developmental signaling and embryonic patterning in Xenopus laevis ( African clawed frog ).
- The catenins also is believed to be involved in the regulation of cadherin function during tissue morphogenesis and tumorigenesis.
Mention the functions of the Cadherin family of CAMs?
- ensures cell adhesion in desmosomes and adheren junction of occluding junction.
- participate in embryonic development.
- participate in tumor metastasis
- play a role in morphogenesis
- Play a critical role during development (cell sorting).
briefly describe the integrin family of CAMs?
- are family of heterodimer glycoproteins
- which are calcium-independent adhesion molecules
- mediate cell-cell and cell-ECM adhesion
what are the functions of integrin?
- Bind epithelial and muscle cells to laminin in the basal lamina
- Allow platelets to stick to exposed collagen in a damaged blood vessel
- Allow white blood cells to adhere to fibronectin and collagen as they move
- role in the cell cycle.
- attachment of cell to ECM
briefly describe the selectin family of CAMs?
- is a family of glycoproteins which are calcium-dependent adhesion molecules
- they are single chained with > NH2 terminal c-type
>with consensus repeats
> transmembrane domain
> and a cytoplasmic tail. - NH2 terminal c- type allows it to bond with specific carbohydrate ligands.
what is the function of selectin?
- involves in lymphocyte homing
- plays an important role in inflammation processes.
- leukocyte migration
briefly describe the immunoglobin superfamily of CAMs?
- are a family of soluble proteins that have Ig domain formed by disulphide bonds.
- has 6 major classes of Ig domain:
- ICAM 1 ( Intracellular adhesion molecule 1 )
- ICAM 2( Intercellular adhesion molecule 2 )
- ICAM-3
- V-CAM-1( Vascular cell adhesion molecule1 )
- PE-CAM-1( Platelet endothelial cell adhesion molecule 1 )
- MAD-CAM-1 ( the mucosal addressin cell adhesion molecule 1 )
what are the Functions of the Ig superfamily?
- play a role in the immune system.
2. leukocyte extravasation
