Lecture 15 - Extracellular Matrix Flashcards
what type of tissues have little ECM
epithelial, muslce and nervous
what provides the strength in epithelial, muscl and nerous tissue
intermediate filaments
cell-cell junction
what does the protein composition of the ECM determine
the physical/mechanical proprties o the tissue
e.g. can be soft and transparent (eye)
or hard and dense (bone)
what important fibrous protein is a key compoent in ocnnective tissue
collagen
lots of types but collagen I makes up most
what does an increase in collagen mean
collagen I content correlates with tissue stiffness
e.g. low in brain but high in bone
what do SUN and KASH proteins do
link filamens in cytoplasm to nuclear lamins in the nucleus
can cause changes in gene expression (tumors more ikely to form in stiffer tissue)
what makes collagen in bone
osteoblast cells
deposits oriented fibres of collagen which are joined by calcium deposits
what re the 2 main components of the basal lamina
laminin
collagen IV
what cells make collagen in sikn/tendon
fibroblasts
where does trimerisation of pro-collagen (precursor to collagen) occur and what does it require
in ER
needs vit C - scurvy
procollagen = vry large, so how might it get transported
via cisternal maturation in golgi
too big for typical vesicles
where does procollagen assemble into fibrils
outside the cell
can c=onyl occur AFTER been cleaved by protease
how do collagen cfibres get properly aligned
cells will deposit them in an oriented way
and then cells eg fibroblasts will rearrange them by pulling on them
bit of a recap, what do protrusions in migrating cells adhere to the surface of the basal lamina with
the focal contacts which contain integrins
and the contractile actin bundles attach to focal contacts
what are integrins
TM proteins that link ECM to cytoskeleton
