Lecture 5: Cell Adhesion Molecules Flashcards
1
Q
Name the two components of the Basement Membrane
A
basal lamina
reticular lamina
2
Q
what does the basement membrane separate?
A
an epithelial layer from it’s CT support
3
Q
what is the average thickness of the basement membrane?
A
50-80 nm thick
4
Q
which component of the basement membrane is produced by the epithelium?
A
basal lamina
5
Q
which component of the basement membrane is produced by the connective tissue?
A
reticular lamina
6
Q
name the five components of the basal lamina
A
laminin fibronectin type IV collagen entactin proteoglycans
7
Q
name two ways type IV collagen differs from type I
A
does not form fibrils
is produced by epithelial cells, type I is produced by fibroblasts
8
Q
which of the five components of the basal lamina is the major component?
A
laminin
9
Q
Laminin consists of how many chains? and what are their names?
A
3 chains
alpha, beta, gamma
10
Q
Laminin has binding sites for 4 molecules, name the four molecules that bind….
A
integrins, type IV collagen, entactin, proteoglycans
11
Q
a protein made up of two polypeptide chains that are cross-linked by disulfide bonds.….?
A
Fibronectin
12
Q
Fibronectin comes in 2 forms, name them
A
Cellular form and plasma form
13
Q
The cellular form of _____ protein, is produced by fibroblasts…..
A
fibronectin
14
Q
the plasma form of fibronectin is secreted into the bloodstream by what cells?
A
hepatocytes
15
Q
Heparin is what type of molecule?
A
proteoglycan
16
Q
Fibronectin has binding sites for 4 molecules, name them…..
A
integrins, collagen, fibrin, proteoglycans(heparin)
17
Q
True or False: Fibronectin and Laminin both have binding sites for 5 different molecules
A
False: they both bind 4
18
Q
What does CAM stand for?
A
cell adhesion molecules
19
Q
CAMs are divided into 2 groups, depending upon their need for ______ in their interactions with other molecules.
A
Calcium ions
20
Q
Name the 2 groups of CAMs
A
calcium dependent
calcium independent
21
Q
Cadherins & Selectins belong to which group of CAMs?
A
calcium dependent
22
Q
Integrins & Immunoglobulin superfamily molecules, belong to which groups of CAMs?
A
calcium independent
23
Q
Which CAM binds to cadherins?
A
cadherins
24
Q
Which CAM binds to carbohydrates?
A
selectins
25
This CAM binds to molecules in the extracellular matrix....
Integrins
26
This CAM binds to Integrins.....
immunoglobulin superfamily molecules
27
Name the four CAMs we discussed in class
cadherins
selectins
integrins
Ig Superfamily
28
Which CAMs form stable types of junctions?
Cadherins & Integrins
29
_____ is a major component in calcium-mediated adheren junctions. And what is the purpose of these junctions?
Classical cadherins
| junctions between epithelial cells-locking them together
30
what are the 3 types of classical cadherins? and where are they found?
E-cadherin ---- epithelial tissue
N-cadherin ---- nerve cells
P-cadherin ---- placenta
31
Desmocollins & Desmogleins, fall into what category?
Non-classical cadherins
32
Non-classical cadherins are found where?
Desmosomes
33
name the most common type of cadherin
E-cadherins
34
True or False: E-cadherins form tetramers via a RGD binding face
False:
| form dimers via HVA binding face
35
T/F E-cadherins are found at the base of extracellular end of cadherin molecule
False: found at the tip
36
in E-cadherins, calcium binds to _____ ____ domains, and facilitate ___-homophilic dimers
4 extracellular domains
| cis-homophilic
37
Loss of E-cadherins is associated with invasive behavior of ____ cells
tumor cells
38
what does HVA binding face stand for?
histidine-valine-alanine
39
____ are small proteins that link cytoplasmic end of a cadherin with cytoplasmic actin
catenins
40
T/F: Actin filaments act as skeletal structure in the extracellular matrix
false: intracellular matrix
41
How many forms are there of catenins? Name them
3 forms
beta & gamma are plakoglobin catenins
alpha catenin
42
____ form(s) of catenin bind to cytoplasmic end of a cadherin
beta & gamma
43
___ form(s) of catenin bind directly to cytoplasmic actin
alpha catenin
44
what is the major function/purpose of catenins?
Catenins serve as major interface between the cadherins that hold adjacent cells together, and the actin cytoskeletons of those cells
45
Selectins bind to carbohydrates, thus they belong to the ____ group
lectin group
46
Selectin binding site for _____ is located at the CRD, at the extracellular end of the Selectin. What does CRD stand for?
carbohydrates
carbohydrate-recognition domain
47
____ binding sites are also found near the CRD on selectins, and ____ is required for the binding of it
calcium
| calcium
48
Define 'extravasation' and give another name for it
Movement of a cell from blood stream to tissue
transendothelial migration
49
____ are involved in the mvt of _______ from blood to tissues, this type of mvt is also called ________
Selectins, leukocytes, extravasation
or
transendothelial migration
50
Hey Arnold! TV show relates to the gross structure of which CAM?
Selectins
51
Name the 3 classes of Selectins and what they are associated with?
P-selectins ---- platelets
E-selectins ---- endothelial cells
L-selectins ---- leukocytes
52
____ are glycoproteins that are mainly involved in cell-to-extracellular matrix interactions
Integrins
53
Integrins bind to both _____ matrix & _______
extracellular matrix & cytoskeleton
54
1 alpha subunit and 1 beta subunit make up _____
Integrin
55
Integrins bind to which two molecules in the extracellular matrix? What type of molecules are they?
Fibronectin & laminin
protein components of the basal lamina
56
T/F: Integrins interact with HVA sequences in fibronectin and entactin
False:
RGD sequence- Arg-Gly-Asp
in fibronectin and laminin
57
Laminin and Fibronectin interact with 3 molecules in the basement membrane.....name them
entactin, proteoglycans, collagen
58
Tonofilaments refer to ______
intermediate filaments such as keratin
59
In _______ integrins link the _____ domains of cells to the extracellular matrix via intracellular tonofilaments
hemidesmosomes
| basal domains
60
Members of which family possess an extracellular segment with one or more folded domains, which is characteristic of ______?
immunoglobulin superfamily
immunoglobulins
61
_____ is a neutral adhesion molecule, and a member of what?
N-CAM
Ig Superfamily
mediate homophilic & heterophilic interactions
62
Name the 3 members of the Ig superfamily
N-CAM
I-CAM-1
I-CAM-2
63
Which member of the Ig superfamily facilitates transendothelial migration of leukocytes? And define this mvt.....
I-CAM-1
| moving across endothelial barrier of blood vessel into the surrounding tissues
64
what are the three categories of junctional complexes?
adherens
occludens
gap junctions
65
this type of junction is associated with lateral domains, and is of the adheren variety. also associated with tonofilaments
desmosomes
66
this type of junction is associated with basal domains and with intracellular tonofilaments.
hemidesmosomes
67
tonofilament is another name for
intermediate filaments
68
explain the difference between zona adheren and zona occluden
adherens help adhere neighboring cells while occludens stop paracellular transport
69
zonulas imply what type of junction referring to their structure?
belt-like junction
| surround the cell circumference
70
molecular complexes that anchor cells together and reinforce tissue integrity, found on basolateral domains
adherens
71
molecular complexes that create impermeable barriers to prevent paracellular transport, which helps to maintain concentration gradients
occludens
72
molecular pores that enable cells to quickly trade ions or small molecules to assist in cell to cell communication
gap junctions
73
differentiate between zonula and macula. are they associated with intracellular actin or tonofilaments?
zonula - complex travels all the way around the cell like a belt, intra cell actin. can be adheren or occluden
macula - spot or snap junctions, intra cell tonofilaments. are adheren only
74
anchoring junctions, with intercellular spaces filled with cadherin proteins: desmogleins & desmocollins
adherens
75
in adherens cadherin proteins are anchored to ______ plaques, which contain desmoplakin & _______
cytoplasmic plaques
| plakoglobin
76
are desmogleins or desmocollins associated with the skin disease: pemphigus foliaceus?
desmogleins
77
zonula and macula adherens are mediated by interactions with _______
cadherins = desmocollins & desmogleins
78
anchoring junctions that connect the basal domain of epithelium to the basal lamina
hemidesmosomes
79
a hemidesmosome consists of: a ________ plate associated with ________ such as keratin. a _______ plaque linking the hemidesmosome to the basal lamina via filaments and ______.
cytoplasmic plate
tonofilaments
membrane plaque
integrins
80
a hemi/desmosome are which type of junction?
macula adherens
81
T/F: desmosomes link one cell to the basal lamina
false: hemidesmosomes link a cell to the basal lamina
desmos link cell to cell
82
claudins and occludins are ______ proteins, responsible for the _______ properties of the tight junction
transmembrane proteins
| occlusive properties
83
these 2 proteins attach intracellularly to proteins ZO-2 and ZO-3
claudins
| occludins
84
zonula occluden proteins facilitate interaction with the intracellular ______ filaments?
actin filaments
85
______ are spots that anchor the cell to the extracellular matrix via integrins and intracellularly to actin filaments.
focal adhesions
86
connexons are associated with ____ junctions
gap junctions
87
a gap junction allows cells to directly.....?
communicate with one another
88
how many subunits does a connexon have?
6 subunits called connexin - form a hexagon with a hollow center
89
a high concentration of what ion, causes gap junctions to close?
high calcium concentrations
