Week 11 - ECM Organization Flashcards
In the ECM, what does Collagen provide?
Provides tensile strength; resists pulling forces.
What do fibriallar collagens form?
Form rigid cables; gnerally composed of 3 chains wound in a triple helix.
In the ECM what is collagen secreted by?
Secreted by fibroblasts; epithelial and smooth muscle cells.
What is a glycoprotein?
A protein with any kind of sugar on it.
What are Proteoglycans?
Proteins modified with glycosaminoglycans (GAG).
What is a GAG?
glycosaminoglycans; long linear chains of a repeating disaccharide (2 repeating sugars); highly negatively charged.
Proteoglycans have at least one side chain of what?
One sugar side chain that MUST be a GAG.
All proteoglycans are glycoproteins, but not what?
NOT vice versa.
What are the 2 kinds of glycoproteins?
- Proteoglycans in the ECM
2. Secreted glycoproteins
Proteoglycans fill what?
They are space filling.
What is Hyaluronan?
A simple GAG; long cain of repeating disaccharide subunits.
Hyaluronan is sometimes just a GAG, but also sometimes what?
Also sometimes linked and PART of a proteoglycan.
Most GAG’s are synthesized where?
Synthesized inside the cell on proteins, and exocytosed.
Hyaluronan is spun directly from where?
Directly from the cell surface by a membrane complex protein.
What does Elastin give tissues?
Gives tissues elasticity.
Networks of elastin stretch and relax like what?
Like a rubber band.
What does Fibronectin do in the ECM?
It binds collagen and cell surface receptors?
What is the structure of a Fibronectin?
- a dimer linked by disulfide bonds
- The RDG site is the cell binding site.
Each fibronectin is composed of different what?
Several different linked domains; each having a different function.
The basal lamina underlies all what?
Underlies all epithelia.
Basal lamina influences cell what?
Influences cell polarity.
Epithelial cells do what to the basal lamina?
They secrete what influences the basal lamina.
What 3 things do Basal lamina surround?
- Muscle
- Fat cells
- Schwann cells
In the kidney, the basal laminal does what?
It divides two cell sheets; acts as a selective filter.
The basement membrane/basal lamina prevents what?
Prevents fibroblasts in the underlying connective tissue from interacting with epithelial cells.
The basement membrane allows for the passage of what?
Allows the passage of macrophages and lympocytes.
How does Laminin organize the basement membrane?
Organizes by interacting with other components of the ECM and integrin in the plasma membrane
What 2 components of the ECM are involved in cell migration?
- Fibronectin
2. Laminin
Laminin is a Trimer of what?
- a-laminin (alpha)
- B-laminin (beta)
- y-laminin (gamma)
Laminin is shaped like what letter?
Like a T.
What do hemidesmosomes do for the epithelial cells and basal lamina?
They spot-weld epithelial cells to the basal lamina; also spot-weld other cells to their ECM.
Keratin filaments are linked to what inside the cell?
They are intermediate filaments inside the cell that are linked to laminin in the ECM.
How are Keratin filaments linked to laminin in the ECM?
Linked through interaction with the transmembrane protein integrin.
Integrins interact with laminin to organize what?
To organize the basement membrane.
