Tissue Architecture Flashcards
What is collagen’s main function?
Main structural protein in ECM/ connective tissue and basal lamina
On what end of the actin filament does growth occur with ATP bound actin?
+ end
What happens to collagen in lumen of ER and Golgi apparatus?
self-assembly of the tropocollagen molecule:
disulfide bond formation in C-terminal extensions –> triple helix formation
On what end of the actin filament are there more ADP-bound actin; where shrinkage occurs?
- end
What do proteoglycans do?
in ECM and connective tissue
combo of this and collagen forms cartilage
What ehler-danlos mutations are autosomal dominant?
mutations to genes for collagen itself
Where are intermediate filaments often anchored to PM?
at cell-cell junctions
What form are intermediate filaments in?
coiled-coil dimer (can make tetramers)
In scurvy, what enzymes are affected?
What molecule does this affect?
Prolyl and lysyl oxidase need iron and ascorbate to function –> don’t have w/out vit c
screws up collagen synthesis
What cell functions are microtubules used for?
form mitotic spindle = important for mitosis
cilia
flagella
What is a tubulin heterodimer made of?
alpha and beta tubulin
What happens to collagen outside of the cell?
cleavage of propeptides –> remove N and C terminal extentions –> collagen
What proteins are in the basal lamina?
laminin
collagen IV
fibronectin
What mesh-like structure do intermediate filaments make up?
nuclear lamina
What does elastin do?
elastic protein in connective tissues
allows tissues to regain shape after stretchin
What cell function(s) are actin filaments essential for?
movements: locomotion, phagocytosis, cell division, contraction, etc
What is F-actin a polymer of?
G-actin
What are the three types of cytoskeletal filaments you should know?
intermediate filaments
Microtubules
microfilaments
How is collagen structured?
trimeric:
forms triple helix
What happens to collagen in the Rough ER?
synthesis of preprocollagen –> procollagen inserted into ER lumen
How do microtubules grow?
at plus ends from gamma-tubulin ring complexes of the centrosome
What cytoskeleton filaments are unstable bc they grow and shrink a lot, but are stabilized by association w/ other proteins?
microfilaments (actin)
What does fibronectin do?
linker molecule in ECM; anchors cells to collagen or proteoglycan substrates
What filament has great tensile strength?
intermediate filaments
What types of collagen are deformed in Ehler-Danlos?
I, III, V
How does laminin exist?
What does it do?
as a heterotrimer
T shaped w/ alpha, beta, and gamma parts
part of basal lamina?
What ehler-danlos mutations are autosomal recessive?
mutations to enzymes used in synthesis
What are anchoring junctions?
cell-cell or cell-matrix
Where are extracellular matrix and basal lamina components produced?
in cell and then secreted out
What happens to collagen in the ER lumen?
proline and lysine get hydroxylated –> selected hydroxylysine residues get glycosylated
What happens to collagen in the secretory vesicle?
procollagen prepared for secretion from cell
what drug binds and stabilizes microtubules?
taxol
