ECM Flashcards
ECM
Function: Different per tissue use
Ex: filtration in kidneys but gives strength to tendons
Epithelial tissue
Little ECM in these cells
also known as basement membrane or basal lamina
Components of ECM
- ) Proteoglycans
- ) Fibrous Proteins
- ) Adhesive Proteins
Proteoglycans
Found:
- ) Mucus
- ) Synovial fluid
Chondroitin sulfate and hyaluronic acid
(Precursor is glucosamine)
Fibrous Proteins
Provide structure
Made up of amino acids
Types of fibrous proteins in ECM:
- ) Collagen
- ) Elastin
Collagen
Most abundant protein in the body
Function:
- ) resist force
- ) different types vary for structural role
- ) ECM function: support and strength
Type 1 Collagen
Most Abundant
Location: bones, skin, tendons
Type 2 Collagen
Location: hyaline cartilage
Body specific location: end of ribs, larynx, trachea and bronchi
Component for filtration in kidneys: Basement membrane and eye lens
Elastin
Rubber like connective tissue
Location:
- ) lung
- ) large arteries
- ) elastic ligaments
Osteogenesis Imperfecta
Brittle bone
Inherited: mutation in collagen gene
Type 1: most common and increased risk for fractures before puberty
Type 2: lethal around birth
Ehlers-Danlos Syndrome
Genetic defect of fibril collagen
Effects joints and some affects skin
Marfan Syndrome
Autosomal dominant: gene mutation necessary for elastin
Features: long limbs, near-sighted, tall stature, abnormal joint mobility
Antitrypsin Deficiency
WBC in lungs produce elastase (elastase digests elastin)
Destruction of elastin in lungs
Cell adhesion
Cell-cell
Cell-matrix: adhesion receptors in the cell membrane bind to the ECM
Use for adhesions: viral infections, cardiovascular disease, bone and joint issues
Protein and carbs are important in forming these interactions.
CAMs
Transmembrane proteins that are embedded in the plasma membrane
Homophilic binding: CAM on 1 cell can bind to same type of CAM on adjacent cell
Heterophilic binding: CAM can bind to different type of CAM on adjacent cell
Types of CAMs
- ) Cadherins
- ) Selectins
- ) Immunoglobulin superfamily
- ) Intergrins
Cell junctions
Anchoring junctions
- ) Adherens
- ) Desmosomes
- ) Hemidesmosomes
Tight junctions: control flow of ions
Gap junctions
Anchoring junctions
- ) Adherens: Join actin bundles between cells
- ) Desmosome: anchors filaments between cells
- ) Hemidesomosome: anchors filaments to basement membrane
Tight Junctions
Holds epithelial cells together and prevents leakage (leaky gut)
Cell Adhesion molecules
- ) cadherins
- ) integrins
- ) selectins
- ) immunoglobulin superfamily
Cadherins
Holds cells together to maintain integrity of tissue
Binding site: Bind to ______ on another cell
Some are inside the cells
CALCIUM is required for binding
Long lasting bond
Integrins
Receptors are in hemidesmosomes
Regulate cell-to-cell and cell-to-ECM adhesions
Very weak
Ligands:
- ) cell-to-cell: binds to members of the immunoglobulin superfamily
- ) Cell-to-ECM: binds to arginine-glycine-aspartic acid residue in collagen and fibronectin
Important for signaling
- ) outside-in
- ) Inside-out
Selectins
Short term
Cell-to-cell adhesions
Function:
- ) Mediate WBC migration to areas of inflammation
- ) Important for the immune system
_____ on one cell binds to lectin on another cell
Immunoglobulin Superfamily
Cell-to-cell adhesion
Function:
1.) promote adhesion of WBC to endothelium of blood vessels during injury
Includes:
- ) Intercellular adhesion molecules (ICAM)
- ) Vascular cell adhesion molecules (VCAM)
Fibronectin
Fundamental adhesive protein in connective tissues.
Three binding domains:
- ) cell
- ) proteoglycans
- ) collagen
Laminin
Fundamental adhesive protein in epithelial tissues.
Extravasation
Migration of cells from circulation into the tissue
Process:
- ) Rolling
- ) Activation
- ) Firm arrest
- ) Diapedesis- movement of the leukocyte thru the endothelial layer
Slide 39 ECM
