Lecture 3-Cell Junctions/Surface Specializations

Question 1

2 classes of cell adhesion molecoules

Answer 1

Calcium dependent=cadherins, selectins

Calcium independent=integrins, immunoglobulin

Question 2

Cadherins require calcium and maintain _____. They are are stabilized by an ____ cytoskeleton.

Answer 2

cell-cell contacts

actin

Question 3

Binding of actin to cadherins is via ___

Answer 3

catenins

Question 4

Loss of E-caderhin is associated with

Answer 4

tumor metastisis

Question 5

Selectins require calcium and bind to ___ at ____ recognition domains

Answer 5

carbohydrates, carbohydrate

Question 6

Selectins are found on ___ and blood cells, and are important for controlling movement of leukocytes from blood into tissues

Answer 6

endothelia

Question 7

If you add a ____ agent to Calcium dependent adhesion molecoules, Ca will bind the agent and cells will ____

Answer 7

celating

come apart

Question 8

Integrins are not calcium dependent. The binding site of integrin is on its _____ subunit (alpha or beta).

Answer 8

beta

Question 9

The intracellular part of integrin binds to cytoskeletal ____ via binding proteins, while the extracellular portion binds to other ligands (ie laminin, fibronectin, tenascin, vitronectin.)

Answer 9

actin

bound via talin, viniculin, alpha actin

Question 10

Immunoglobulins consist of a _____ on the extracellular portion of the cell.

Answer 10

Cell adhesion molecoule

Question 11

____ and ____ molecoules play an important role in T cell interactions and binding of leukocytes to activated endothelial cells. (part of IgG super family)

Answer 11

ICAM and VCAM

Question 12

_____ junctions determine epithelia polarity and prevent free passage across an epithelial layer by ions/proteins

Answer 12

Occluding (tight)

They separate the apical domain from the baolateral domain)

Question 13

Occluding junctions interact with these 2 transmembrane proteins

Answer 13

Occludin and claudin

Question 14

Nectins and Junctional Adhesion Molecoules (JAMS are present in ____ junctions.

Answer 14

Tight

Question 15

Interaction between occludin and claudin regulates the _____ pathway

Answer 15

paracellular

Question 16

A gene mutation in Claudin 16 causes

Answer 16

renal magnesium wasting syndrome

Question 17

Tight Junctions are important parts of the blood brain barrier and can prevent ____

Answer 17

delivery of drugs

Question 18

_____ are located below occulding juctions

Answer 18

Zonula Adherens

Question 19

Zonula Adherens consist primarily of interactions between ____ and ____. They form a belt-like distribution around the cell

Answer 19

cadherins and catenins

Question 20

Zonula adherens form a strong association due to interaction with ____ filaments in the cytoskeleton

Answer 20

Actin

Question 21

Desmosomes are spot like junctions and are stabilized by _____

Answer 21

intermediate filaments-including keratin and vimentin

Question 22

Pemphigus foliaceus is an autoantibody-mediated blistering disease in which antibodies against _____ cause a loss of adhesion of keratinocytes in the superficial layers of the epidermis

Answer 22

desmoglein 1

Question 23

______ anchor the basal portion of a cell to the basal lamina

Answer 23

hemidesmosomes

Question 24

Hemidesmosomes are the only ____ junction

Answer 24

assymetrical

Question 25

Hemidesmosomes consist of intermediate filaments bound to a protein complex containing ____. The comple is linked by integrins to the basal lamina by ____

Answer 25

plectin, laminin

Question 26

_____ junctions are communicating junctions between cells

Answer 26

Gap

Question 27

In gap junctions, 6 integral proteins called ___ associate to form ____

Answer 27

connexins, connexon

Question 28

Gap junctions link cells both chemically and _____ and are found in _____ muscle cells

Answer 28

electrically, cardiac

Question 29

A mutation in connexin 26 causes ____. A mutation in connexin 32 causes ______ _____ degeneration. Connexin 50 mutations can cause _____

Answer 29

deafness peripheral nerve (aka Charcot-Marie-Tooth neuropothies) cataracts and blindness

Question 30

_____ increase surface area for absorption and contain an actin filament core that links into the _____ web.

Answer 30

Microvilli | Terminal

Question 31

Microvilli are often found in the ____

Answer 31

small intestine

Question 32

Cillia and flagella both have a ____ array of highly stable MTs

Answer 32

9 + 2

Question 33

Cilia consists of hairlike appendages that move fluid and develop from ____ bodies

Answer 33

basal

Question 34

2 functions of cilia: 1 in lung, 1 dealing with reproduction

Answer 34

sweep mucus and particulates away in lung | move egg to oviduct

Question 35

Flagella act as propellor for _____ motility. ____ provides force for movement

Answer 35

sperm, dyneins

Question 36

Loss of dynein in cilia leads to _____ syndrome, which causes poor respiratory clearance

Answer 36

kartagener's

Question 37

Stereocilia have similar structure to microvilli but differ in that they are _____ and _____

Answer 37

longer and branch

Question 38

Stereocilia are typical of the ____ epithelium and cause an increase in ______

Answer 38

epididymal | surface area

Question 39

Leucocyte adhesion deficiency type 1 is characterized by recurren infections and is caused by mutations of _____

Answer 39

integrin

Question 40

Autosomal recessive glanzmann thrombasthenia is due to point mutations in _____

Answer 40

integrin

Question 41

Congenitial Muscular Dystrophy results in muscle weakness and is due to defects in the cytoskeletal linker protein ____

Answer 41

dystrophin it is a major laminin binding integrin species

Question 42

Removal of calcium stops adhesion and makes ______ vulnerable to proteases

Answer 42

cadherins

Question 43

______ are important for controlling movement of leukocytes from blood into tissues

Answer 43

selectins

Question 44

_____ junctions are at the most apical portion of epithelium and define cell polarity.

Answer 44

Occluding

Question 45

_____ adherens is associated with actin and has a while beltlike distribution.

Answer 45

Zonula

Question 46

_____ adherens is associated with Intermediate filaments and has a spotlike distribution

Answer 46

Macula

Question 47

basal bodies of cilia are derived from _____

Answer 47

centrioles

Question 48

Autosomal recessive Glanzmann thrombaasthenia is due to integrin dysfunction and results in _____ dysfunction as well as prolonged bleeding time

Answer 48

platelet

Question 49

______ bullosa causes disruption of the mechanical link between the basement membrane and the basal keratinocyte layer

Answer 49

Epidermolysis