Fom Flashcards Set 4

Front 1

plectin

Back 1

binds IFs to integrins in hemidesmosomes, also crosslinks IFs together, to MTs and MFs. Mutations lead to blistering diseases (variants of epidermolysis bullosa)

Front 2

bullous pemphigoid (BP230)

Back 2

type of adapter protein in hemidesmosomes - there's a disease of the same name

Front 3

collagen XVII

Back 3

another transmembrane component aka BP180 - another type of bullous pemphigoid antigen; regulates function of laminin 5

Front 4

collagen VII

Back 4

connects the epidermis to the dermis.
usually found in close association with hemidesmosomes. extend from basal lamina either to "anchoring plaques" in connective tissue matrix or laop back to the basal lamina. entrap type III collagen in underlying connective tissue.
mutations lead to epidermolysis bullosa - epithelium detached from basement membrane

Front 5

laminin 5

Back 5

connects the epidermis to the dermis, mutation leads to a form of epidermolysis bullosa

Front 6

bullous pemphigoid

Back 6

autoimmune blistering disease that involves destruction of hemidesmosomes
antibody IgG binds to hemidesmosome, calls over mast cells. Mast cells release eosinophil chemotactic factor, attract eosinophils. Eosinophils release proteases which breakdown hemidesmosome

Front 7

eosinophil

Back 7

combat parasitic infections. Crystalline center, lots of granules filled with 1) eosinophil peroxidase (binds microorganism facilitating theri killing by macrophages 2) major basic protein (MBP) - binds and disrupts membranes of parasites 3) Eosinophil cationic protein - works with MBP to fragment parasites
involved in bullous pemphigoid - release proteases to break down hemidesmosomes

Front 8

focal adhesions

Back 8

connect actin cytoskeleton to extracellular proteins in basal lamina via integrins; provide adhesion, traction during cell motility
colocalization of actin and actin binding

Front 9

selectins

Back 9

expressed on Lymphocyte, Endothelial cell, and Platelet (L, E, and P selectin)
When there's an infection, selectins expressed on endothelial cells, loosely bind leukocytes to induce rolling
- in general, bind carbohydrate domains on other cells with weaker adhesion that cadherins

Front 10

Intracellular Cell Adhesion Molecules

Back 10

bind integrins on the surface of leukocytes. Tighter binding

Front 11

basement membrane

Back 11

specialized connective tissue - thin layer of extracellular matrix that underlies all epithelial cells, all endothelial cells, surrounds all muscle fibers and nerves
- see with PAS stain

Front 12

Lamina lucida

Back 12

made up of laminin, 3 short arms, one long arm - globular domains at each end. 3 polypeptides, alone are alpha helices, form a coiled coil together.
makes up top layer of basal lamina

Front 13

alpha laminin polypeptide

Back 13

1 of 3 polypeptides that make up laminin. binds heparan sulfate sidechain of proteoglycans

Front 14

gamma laminin polypeptide

Back 14

1 of 3 polypeptides that make up laminin. has binding site for the core protein of the proteoglycan.
Has a proteoglycan binding site, an enactin attachment sit, and an integrin binding site

Front 15

beta laminin polypeptide

Back 15

1 of 3 polypeptides that make up laminin. has a heparan sulfate binding site and an integrin binding site

Front 16

type IV collagen

Back 16

composed of 1 collagenous domain and 2 noncollagenous (7S and NC1) domains. Makes up the lamina densa.

Front 17

entactin

Back 17

binds laminin and collagen networks together! remember entactin binding site is within the short arm of laminin on the gamma subunit

Front 18

integrins - job in basement membrane

Back 18

attaches laminin to epithelial cells via focal adhesions. allows cells to crawl around on basement membrane OR to firmly attach. mutations in the laminins or integrins - detachment of epithelium from basement membrane

Front 19

junctional epidermolysis bullosa

Back 19

upper layer is off dermis. Mutations in laminins or integrins - epidermis sloughs off, perinatally lethal

Front 20

fibronectin

Back 20

dimer, formed by disulfide bonding at C-terminal. 2 primary domains - collagen binding domain and cell binding domains. Binds integrin and type IV collagen, heparin, and fibrin. Allows cells to interact with basement membrane.

Front 21

proteoglycan

Back 21

core protein + specific sites to which glycosaminoglycan side chains attach. (proteoglycans are GAGs + core protein + linking)

Front 22

glycosaminoglycan

Back 22

side chains of GAG bind to proteoglycans. long sugar chains that are highly sulfated, gives basement membrane a negative charge. This allows glycosaminoglycans to bind to growth factors.

Front 23

lamina reticularis

Back 23

synthesized by the underlying fibroblasts in connective tissue. consists of type III collagen. Connects basal lamina to underlying stroma (connective tissue). Glomerular basement membrane doesn't contain a lamina reticularis!

Front 24

ankrin

Back 24

in dynactin complex, involved in holding onto vesicle, spectrin, and Arp1

Front 25

calmodulin

Back 25

involved in the myosin activating signal pathway. Ca binds calmodulin which activates myosin light-chain kinase. This phosphorylates the myosin, which causes activation of myosin.

Front 26

collagen

Back 26

triple helix, composed of 3 polypeptides. Collagen subunit - 1 polypeptide. Collagen molecule - all 3. Each subunit is linear with glycine at every third amino acid. Also, rich in proline.

Front 27

what is the progression of collagen synthesis?

Back 27

procollagen assembles into a triple helix --> procollagen molecules, are secreted into the extracellular space, noncollagenous parts are cleaved --> tropocollagen, aggregates ---> collagen fibrils undergo crosslinking, aggregation --> collagen fibers.

Front 28

collagen I

Back 28

most abundant, forms fibers, skin, bone, ubiquitous. In bone, formed from osteoblasts. In tendon and skin, from fibroblasts, in dentin - odontoblasts

Front 29

collagen II

Back 29

networks of fibrils - doesn't go onto assemble fibers, but forms networks of fibrils. Hyaline cartilage, elastic cartilage - formed by chondroblasts. In menisci of knee, for example

Front 30

collagen III

Back 30

in bone marrow and lymphoidal organs. synthesized by reticular cells. forms reticular fibers - need a special stain to see. In spleen, liver, lymph nodes

Front 31

collagen IV

Back 31

does not form fibers or fibrils. Forms networks of procollagen in the lamina densa! synthesized by epithelial cells. contributes to the filtration barrier created by the basement membrane in the glumeruli of the kidneys

Front 32

elastic fibers

Back 32

add elasticity to tissues. Stretch/relax because have crosslinkers which provide stretch. Composed of tropoelastin, fibrillin I, II, and microfibril associated glyco-proteins (MAGP). individual components are made by the cell (in RER), but are assembled in extracellular environment. found in tissues with a lot of stretch - ear, nose, blood vessels

Front 33

fibrillin I and II

Back 33

one component of elastic fibers. fibrillin I is for force-bearing structural support
fibrillin II regulates the assembly of the elastin
synthesized by fibroblast or smooth muscle cell

Front 34

MAGP

Back 34

microfibril associated glyco-proteins. one component of elastic fibers

Front 35

pro-elastin, tropoelastin

Back 35

proelastin is what's made in the RER. THen, its secreted and processed by the golgi til it becomes tropoelastin, then it combines with MAGP and fibrillin I and II extracellularly

Front 36

MMPs

Back 36

matrix metalloproteases. Degrade extracellular matrix proteins. Depend on metal ions for catalytic activity.

Front 37

TIMPs

Back 37

binds to active MMPs, shuts down activity

Front 38

fibroblasts

Back 38

synthesize proteoglycans, collagen, and elastin

Front 39

macrophage

Back 39

phagocytize foreign material. In different locations with different names. Can only distinguish when see injested material, kidney shaped nucleus

Front 40

lymphocytes

Back 40

in abundance in connective tissue in duodenum. Can differentiate into plasma cells when activated and plasma cells produce immunoglobins

Front 41

plasma cell

Back 41

bigger than lymphocyte. clock-shaped nucleus with heterochromatin on the periphery. Well developed RER and extensive golgi because lots of protein synthesis!
Make antibodies

Front 42

Mast cell

Back 42

function in allergic response. Contains receptors for IgE class antibodies.
1) antigen bridges IgE
2) bridging of receptors --> signalling cascadde resulting in mobilization of cytosolic Ca2+
3) triggers release of granules in mast cells, such as histamin, proteases, proteoglycans, and cytokines
Also functions in bullous pemphigoid response

Front 43

EN-RAGE

Back 43

natural ligand for RAGE. Highly expressed in clots formed at site of a wound. Draws macrophages and fibroblasts to site. Initial increase in MMPs to provide access to cells and damaged tissue. Then, macrophages and fibroblasts degrade MMPs and synthesize collagen to heal wound (1st collage III, then collagen I)

Front 44

AGE

Back 44

advanced glycation end products. bind to RAGE, connective tissue becomes like glue, preventing macrophages and fibroblasts from getting to wound. The cells in clot continue to synthesize MMPs which break down new collagens, wound doesn't heal.

Front 45

Assumptions in M-M?

Back 45

- [substrate]>>>>[enzyme]
- in steady state
- measure in early times so that reaction is relatively irreversible

Front 46

kcat

Back 46

turnover rate of an enzyme. Number of times a single enzyme can complete the cycle in a given amount of time, if all reactants are available. if kcat increases, vmax will increase!
kcat*[enzyme] = Vmax

Front 47

pre-proenzyme (protease)

Back 47

as translated from mRNA

Front 48

pro-enzyme (protease)

Back 48

aka zymogen. in right location, leader sequence cleaved, inactive

Front 49

mature proteases

Back 49

other region cleaved - active!!!