Lecture 15 Flashcards
the matrix controls the mechanical propertieis of tissues - this is determined by ____
the specific protein composition of the ECM
what percentage of the protein mass in our body is made up of collagens?
25%
_____ content correlates with tissue stiffness
collagen I
SUN and KASH proteins link filaments in the _____ to nuclear lamins ______
cytoplasm
inside the nucleus
cells alter gene expression in response to changes in the ____ of their environment in a mechanism involving ___ and __ complexes
stiffness
SUN
KASH
____ is a key component of bone
collagen I
osteoblasts do what?
deposit the ECM in bone
___ and ____ are the main components of the basal lamina
laminin
collagen IV
collagen is made by connective tissue cells: (2)
osteoblasts (bone)
fibroblasts (skin, tendon)
collagen is a single ____ that is translated at _____ and passed through the ER membrane into the ____ where it forms a triple stranded _______
polypeptide chain
endoplasmic reticulum
lumen
helical procollagen molecule
collagen is secreted as a _____ called ____
precursor
procollagen
collagen fibres must be ___
properly aligned
ECM diseases include (3)
- abnormally stretchable skin
- brittle bone disease
- skeletal abnormalities (short bones, abnormal bone structure) - achondroplasia
integrins
trans-membrane proteins in the plasma membrane
link ECM to cell’s cytoskeleton
type of cytoskeleton linkage depends on context
GAGs
glycosaminoglycans
- large, neg charged polysaccharides
- strongly hydrophilic
- occupy huge volume relative to mass
proteoglycans
extracellular secreted proteins with covalently linked GAGs
cartilage is tought and resists compression why?
GAGS generate swelling pressure (bc they bind water molecs)
hyaluronan is only made of ___
carbohydrate (contains no protein at all)
hyaluronan is synthesized by _____
hyaluronan synthase - at the plasma membrane
is extruded directly into the extracellular space
