Shemanko Lecture 1

Question 1

How do dermis and epidermis cells interact to produce the basement membrane?

Answer 1

The epidermis cells secrete proteins and the dermis cells secrete proteins which both contribute to the basement membrane

Question 2

What are the differences between epidermis cells and dermis cells?

Answer 2

Epidermis on top of basement membrane, dermis is on bottom. The dermis is a connective loose tissue, the epidermis has closely packed cells

Question 3

Is the basement membrane an actual membrane?

Answer 3

No, is another word for the extracellular matrix

Question 4

What six things are cellular reactions required for?

Answer 4

Intracellular communication
Survival
Tissue strength
Organ function
Immune system function
Embryonic development

Question 5

What 4 families of integral membrane proteins mediate cell cell adhesion?

Answer 5

selectins
Immunoglobulin super family
members of the integrin family
cadherins

Question 6

How do cadherins interact between cells?

Answer 6

Cadherins interact head to head and keep on going until they interlock

Question 7

How do selectins interact between cells?

Answer 7

Selectins bind to sugar complexes on cell 2 with the ends of their protein which are called lectins. The sugar complex is specialized to the type of selectin: Can be L, E, or P and usually a cell type expresses one form of this protein.

Question 8

How do immunoglobulin proteins interact between cells?

Answer 8

proteins have immunoglobulin domains,, sometimes the domains interact with eachother, or the domains interact with receptors called integrins

Question 9

What are the features of cadherins? Where do they bind, how do they bind, what do they do, where are they?

Answer 9

Cadherins bind to other cadherins on close by cells
they are calcium dependent proteins
they mold cells into cohesive tissues in the embryo and hold them together in the adult
when they are lost it can lead to malignancy
you can find caherins at synapses, adherens junctions, and desmosomes

Question 10

How do cadherins mediate cell differentiation in am embryo? What experiment confirms this?

Answer 10

We took an embryo and mixed up the cells, over time the embryo differentiated to what it once was. Through cadherins cells adhere to only cells of the same type.

Question 11

What confirms that cadherins will bind to other cadherins of the same cell type regardless of species?

Answer 11

By creating a blastocyst from pig cells injected by experimentally derived stem cells, blastocysts formed so cadherins could bind the cells that were similar even if they were from a different animal.

Question 12

What are the features of immunoglobulin super family? Where do they bind, how do they bind, what do they do, where are they?

Answer 12

contain immunoglobulin domains that bind to other domains or an integrin family, mediate calcium independent adhesion

Question 13

What VCAMS? ICAMS?

Answer 13

Are IgSF proteins, intracellular adhesion molecules and vascular adhesion molecules
Integrins act as receptors for ICAMS

Question 14

What is the difference between E, P, or L selectins?

Answer 14

E-selectins are present on endothelial cells
P on platelet and endothelial cells, and L on all types of leukocytes

Question 15

What are the features of selectins? Where do they bind, how do they bind, what do they do, where are they?

Answer 15

Selectins bind in a calcium depenent manner, are a family of membrane glycoproteins that bind to specific sugars, they have a small cytoplasmic segment, a single membrane spanning domain, and a large extra cellular portion

Question 16

How do neutrophils move from the bloodstream during inflammation?

Answer 16

1. Endothelial activation: Inflammation activates endothelial cells, that makes selectins increase and they stick more to neutrophils
2. Neutrophil trapping: Selectins bind to sugars (Psgl-1) on neutrophil
3. Neutrophil activation: The platelet activating factor on the surface of endothelial cells activates the G protein coupled receptors on the neutrophil and causes the neutrophil cytoskeleton to change as integrins on it are activated
4. Neutrophil adhesion: Integrins bind to icams and then cells cytoskeleton changes and it excavates- goes through endothelial cells
5. Transendothelial migration

Question 17

How do cadherins stop metastasis?

Answer 17

E-cadherins bind in the primary tumour to stop it from spreading and making secondary tumours