Lectures 5/6 Cell Junctions

Question 1

Understand/explain what purpose various cell connections serve

Answer 1

Tissue structure/integerity
barrier formation
mobility
signaling

Question 2

-Cell to cell or cell to ECM
-General FXN
-If cell signaling how?
-What proteins from junctions are they attacked to Cytoskelton proteins
-How stable are they relative to one another
-What happens if they don’t function Properly

GAP JUNCTIONS

Answer 2

-Are cell to cell
-Used to provide a channel of passage need a voltage, PH or ligand
-Formed w/ Connexins(Connexons)
-Least stable
-If they do not fxn properly then the cell can no transport squabble mols cell to cell

Question 3

-Cell to cell or cell to ECM
-General FXN
-If cell signaling how?
-What proteins from junctions are they attacked to Cytoskelton proteins
-How stable are they relative to one another
-What happens if they don’t function Properly

TIGHT JUNCTIONS

Answer 3

-They are cell to cell
-Seal the gaps between epithelial cells Impermeable barriers for H2O
-Claudins and occluding form tight junctions
-Do not help w/ integrity only help to prevent movement into the cell.
-If they do not work then items can get in, blood brain barrier

Question 4

-Cell to cell or cell to ECM
-General FXN
-If cell signaling how?
-What proteins from junctions are they attacked to Cytoskelton proteins
-How stable are they relative to one another
-What happens if they don’t function Properly

ADHERIN JUNCTIONS

Answer 4

-Cell to cell
-Form an adhesion belt that can sense sheer stress
-Formed via cadherins but need to be bound w/ Ca2+
-The cladherins can also help w/ cell recognition E-Cadherin or N-Cadherin

Question 5

-Cell to cell or cell to ECM
-General FXN
-If cell signaling how?
-What proteins from junctions are they attacked to Cytoskelton proteins
-How stable are they relative to one another
-What happens if they don’t function Properly

Epitherlia mesenchymal transitional

Answer 5

-Cell to cell
-Mobility and changes shape
-Cadherins
-Not stable
-disruption of the cell

Question 6

-Cell to cell or cell to ECM
-General FXN
-If cell signaling how?
-What proteins from junctions are they attacked to Cytoskelton proteins
-How stable are they relative to one another
-What happens if they don’t function Properly

Nonclassical cladherins: Desmosomes

Answer 6

-Cell to cell
-dense plaque holding together
-Noncalsicall cladherins
-Stable

Question 7

-Cell to cell or cell to ECM
-General FXN
-If cell signaling how?
-What proteins from junctions are they attacked to Cytoskelton proteins
-How stable are they relative to one another
-What happens if they don’t function Properly

Hemidesmosomes

Answer 7

-Cell to ECM
-Connect intremedfilaments w/ ECM
-Intergin and collagen
-stable
-He;ps form ECM

Question 8

Glycosaminoglycans

Answer 8

Uncharged neg changed polysaccharides chains

Question 9

Proteoglycans

Answer 9

GAGS covalently attached to proteins

Large molecules used to provide cushions and physical barriers

Question 10

Fibrous proteins

Answer 10

Collagens
resist tensile forces to maintain tissue integrity

Question 11

Glycoproteins

Answer 11

Short branched oligosaccharides chains
facilitate cell attachment

Question 12

C/C ECM w/ Basal Lamina/Basement Membranes

-What FXN serve
-What Structures
-What are major proteins/sugar compounds
-what happens if fails to FNX
Explain the role of matrix metalloproteasese(MMP) in ECM turnover

Answer 12

-Connects cells and can acts as a filter(kidney), Facilaites migration, surrounds muscle and fat
-Laminas, collagens, protease
-They would not have a barrier

MMP actions
-MMPs help w/ cell mobility from adhesive to non-adhesive by degreasing ECM
-Deveolpment can lead to proliferation
-Growth fraction signaling
in CA cells can lead to maglgnancy