Cell-Cell and Cell-Matrix Interactions

Question 0

ECM - Functions

Answer 0

Hold tissue together, strength, elasticity, cushioning, adhesion, provide environmental cues to cell, modulate interactions between cells and their environment, provide a lattice upon which cells can move, involvement in signaling, reservoir for many extracellular signaling molecules that control cell growth and differentiation.

Question 1

ECM - def.

Answer 1

Material found between cells.
Dynamic

Exception - not found between sheets of cells in an epithelial layer

Question 2

ECM - Components

Answer 2

Collagen Fibers
Elastin Fibers
Proteoglycans
multiadhesive matrix proteins

Question 3

How do cells interact?

Answer 3

Intracellular interactions and cell-matrix interactions

Question 4

CAM’s (list)

Answer 4

Cadherins
Selectins
Intergrins
Immunoglobulin

Question 5

Cadherins - def., function, composition

Answer 5

Calcium dependent glycoproteins
Mediate adhesive interactions between homotypic or heterotypic cells
Consists of intracellular, transmembrane and intercellular domains
Broadly distributed or clustered

Question 6

Cadherins - types, works with

Answer 6

E Cadherin - epithelial
P Cadherin - Placental
N Cadherin - neural

Adapter Proteins

Question 7

Adapter Proteins - function, types

Answer 7

Directly or indirectly connect cadherins to the cytoskeleton microfilaments (actin)
Recruit intracellular molecules that function in signaling pathways that allow for bidirectional signaling for cell growth and motility
Alpha and Beta Catenin

Question 8

Down regulation of E-Cadherin

Answer 8

decreases strength of intercellular adhesion and enhances cellular motility - allows cancer cells to cross basement membrane

Question 9

Loss of E-Cadherin

Answer 9

Leads to disintegration of the E-cadherin-catenin complex - results in release of signal molecules which my be involved in cell invasiveness

Question 10

N-cadherin expression in breast tissue

Answer 10

Not normally expressed in normal mammary epithelium

Upregulated in breast cancer (alongside E-cadherin loss)

Question 11

Selectins - Def.

Answer 11

Calcium-dependent vascular adhesion molecules - glycoproteines
Produced by endothelial cells

Question 12

Selectin - Function

Answer 12

Involved in the interactions between the endothelium, leukocytes, and platelets in the inflammatory process

Question 13

Selectin - types/role

Answer 13

E-selectin - endothelial-leukocyte adhesion molecule
P-selectin - recruitment of platelets
L-selectin - found on leukocytes

Question 14

E & P selectin - action

Answer 14

Interact with leukocytes, slow them down near site of infection

Leukocyte recruitment to infection

Question 15

Selectin mediate adhesion

Answer 15

Weak allowing leukocyte rolling along endothelium

Question 16

E- Selectin Overexpression

Answer 16

associated with more positive lymph node metastasis in breast cancer

Question 17

Intergrins - def., components

Answer 17

Cell surface glycoproteins
Receptors for ECM components
extracellular, transmembrane, and intracellular components

Question 18

Integrins - Function

Answer 18

Control organization of the cytoskeleton of migration and extravasion of leukocytes.
Cell adhere to a substrate though their intergrins
Regulate many biologic processes

Question 19

ICAM-1 a.k.a

Answer 19

Intercellular adhesion molecule, I

Question 20

ICAM-1, function

Answer 20

creates a tighter adhesion to stop leukocytes at infected site from rolling along by binding tightly to intergrins on leukocyte surface

Question 21

Leukocyte-adhesion deficiency - def., symp.

Answer 21

Rare genetic defect in synthesis of intergrin subunit.
Patients susceptible to repeated bacterial infection and non-healing wounds because their leukocytes cannot extravasate, migrate and phagocytose bacteria properly

Question 22

Integrin & E Cadherin

Answer 22

Integrin activation down-regulates E-cadherin thus allowing cancer cells to cross basement membrane due to decreased strength of intercellular adhesion and enhancement of cellular motility

Question 23

Integrin signaling

Answer 23

modulates expression and/or activity o matrix metalloproteinases (MMPs) which break down components of the matrix allowing passage of cells.

Question 24

Immunoglobulin superfamily - def., function

Answer 24

Group of adhesive receptors characterized by presence of multiple Ig domains (repeats) in their extracellular regions.
Involved in recognition, binding or adhesion of cells

Question 25

Immunoglobulin superfamily - members

Answer 25

cell surface antigen receptors, ICAM-1, antigen-presenting molecules, leukocyte receptors, growth factor receptors

Question 26

Laminins - def., sturcture

Answer 26

Protein of cell-associated matrices and basement membrane

Large flexible complex of 3 long polypeptide chains (A, B, Y) held together by disulfide bonds

Question 27

Laminins - function

Answer 27

Functional domains that bind to cells, collagen, and other matrix molecules
Bind cells to the basement membrane

Question 28

Laminin-332 - function

Answer 28

Attached cells to basement membrane and inhibits their movement
In Tumors - promote migration
Positive and negative repercussions

Question 29

Defetive laminins cause?

Answer 29

muscular dystrophy type
lethal skin blistering disease
defect of kidney filtration system