Extracellular Matrix Flashcards
Collection of extracellular molecules secreted by cells that provides structural and biochemical support to surrounding cells
extracellular matrix
Where is the EM found?
epithelium, endothelium, connective tissue
Cells contained in EM
- fibroblasts
- immune cells
- fat cells
- bone cells
macromolecules contained in EM
- collagen
- elastins
- proteoglycans
- hyaluronan
- adhesive glycoproteins
two groups of cells in EM
indigenous cells and immigrant cells
4 indigenous cells
Primitive mesenchymal cells
Fibroblasts
White fat
Brown fat
immigrant cells
blood cells (immune system cells) —- plasma cells, monocytes, lymphocytes, etc.
Undifferentiated multipotential stem cells that proliferate and differentiate to give rise to all indigenous cells of connective tissue
primitive mesenchymal cells
main cell of em, secretes most of the macromolecules, spindle shaped reticular cells (can be other shapes)
fibroblasts
- Distributed in the CT of ECM
- energy reserve
- calories (energy) in the form of lipid droplets
- Only vertebrates have specialized cells recognizable as these
fat cells
master regulator of energy balance and nutritional homeostasis (most important function)
adipose tissue
types of fat cells
white, brown, and beige
- Contain a single large lipid droplet full of triglycerides
- Secrete hormones such as leptin,
- Most common fat cell
white fat
- Color refers to the large number of mitochondria
- Specialized fat that dissipates stored energy in the form of heat
brown fat
- Emerge in rodents upon prolonged cold exposure or adrenergic signaling
- Have both overlapping and distinct gene expression form brown fat
beige fat
which cell has a different linegae
brown fat - has the same lineage as a myoblasts
immune system cells
CT — blood and lymph, the interstitial space in the ECM
most abundant protein in human body, formation of a rod composed of a triple helix of polypeptides
collagen
tendons, ligaments, bones, dense CT
fibrillar collagens
polymerize into sheets, found in tissue surrounding organs, epithelial or in some cases a whole animal
sheet forming collagens
example that forms the basal lamina
type IV collagen
fibrillar and sheet collagens, provide and anchor for type IV collagen to the basal lamina
linking collagens
collagen amino acid seuqence
Gly-X-Y
part of the repeating sequence, found in 3rd position of the polypeptide chain, fits into the restricted spaces where the three chains of the helix come together
glycine
frequently proline
X
facilitate the formation of helical conformation of α- chain, because its ring structure causes kink in the peptide chain.
proline
hydroxy proline and hyroxy lysine
Y
residues after their incorporation into the polypeptide chains.
- post translational modification
- stabilizes
- requires oxygen and Vitamin C
- mediated by prolyl and lysol hydroxyls in the rER
hydroxyporline and lysine
vitamin C deficiency
scurvy
swelling and bleeding of the gums, sick, bruised and bleeding, pain and swelling, hair and tooth loss,
scurvy
most prominent in skin and walls of arteries, consists of fibrillar microfibrils
elastic fibers
consists of tandem repeats of hydrophilic and hydrophobic domains
elastin molecules
responsible for the elasticity
hydrophobic domain
responsible for the rubbery elastin
desmosine
stretched elastin are
organized
heavily glycosylated proteins
proteoglycans
one or more covalently attached glycosaminoglycan chain
core protein
long polysaccharides made of repeating disaccharide units (hexuronic acid and hexoasmine)
glycosaminoglycans
Function as adaptor proteins to facilitate attachment between different ECM proteins and ECM proteins and sugars
adhesive glycoproteins
Participate in providing cells with signals required for the development and repair of tissues
adhesive glycoproteins (fibronectin and tenacin)
Thin planar assembly of ECM proteins that supports epithelia, muscle cells and nerve cells outside of the central nervous system
basal lamina
Regulated degradation of ECM is essential for several physiological processes such as
tissue remodeling, wound healing, organ involution
three classes of Zn-dependent proteases
- MMPs - Matrix metalloproteases
- ADAMS (a disintigrin and mellaoprotease)
- ADAMTs (ADAMs with a thrombospondin domain)
what are metalloproteases regulated with
TIMPS (tissue inhibitors of metalloproteases)
Genetic bone disorder
Poorly formed and fragile bones
Caused by abnormalities of collagen I structure or synthesis
osteogenesis imperfecta
Disturbance in the development of cartilage
Mild, severe arrested growth and dwarfism, to congenital lethal
chondrodysplasia
Inherited disorder with long bone overgrowth, defects of the heart valve and aorta
Mutations in fibrillin 1
marfan syndrome
Inherited mutations in the production or processing of collagen
Classical form is autosomal domoninat
Characterized by overly flexible joints, stretchy fragile skin.
More severe forms, blood vessel walls, or intestine will rupture
No cure, only manage symptoms
ehlers-danlos syndrome
two types of adhesive glycoproteins
fibronectin and tenacin
the basal lamina contains
nidogen, laminin, TIV collagen, and perfect that makes a floor”
regulated degradation of ECM (type 1 collagen and elastin)
MMPS
