College aantekeningen
Lecture notes BBS2052
- Vak
- Cell signalling
- Instelling
- Maastricht University (UM)
Do you want to pass your BBS2052 exam but don't want to watch the lecture hereby a the complete discriptive for it
[Meer zien]Voorbeeld 4 van de 41 pagina's
Voorbeeld 4 van de 41 pagina's
In winkelwagengesponsord bericht van onze partner
Verkoper
Volgen
Voorbeeld van de inhoud
43 BBS2004 Lecture notes:Case 1 cellular communication routes:
- Anchoring junction is very important to hold cells together, so that we you bend things in your body
it doesn’t break
-This junction in the epithelial cell of the skin and intestine is needed for flexibility (motility),
reshaping, and barrier, and in the muscle for movement, and strength, and in cardiomyocytes for
heart function (so that the muscle continuous)
4 different types of junctions:
- Occluding junction = Tight junction, seals gap between epithelial cells
- Cell-cell anchoring junction = Desmosomes and adherens junction
- Channel forming junction = Gap junctions
- Cell-matrix anchoring junction = Focal adhesion and hemidesmosomes
- In general, you have a transmembrane adhesion protein, which is bound to adaptor protein, which
is bound to an intermediate filament
- In anchoring junction of epithelial cell, actin is bound to a catenin, which is bound to b/y catenin,
which is bound to a classical cadherin (E, P, N)
- In between cadherins there are hinge regions, and you need calcium to make this region stiff, makes
cadherin stiff, and that can then interact with other stiff cadherin (otherwise they are floppy, and
can’t bind to each other)
- Desmosomes connect intermediate filaments of one cell with another, the transmembrane proteins
of it are desmoglein, and desmocollin, and the adaptor proteins are plakoglobin, plakophilin, and
desmoplakin
- Actin filaments are important for supporting plasma membrane, cytokinesis, cell movement, and
signal transduction
- Microtubules are needed for organisation and transportation
- Hemidesmosomes bind intermediate filaments with extracellular matrix
- The adaptor proteins of hemidesmosomes are plectin, and dystonin, and a6b4 integrin, and
collagen XVII are TM proteins
- Focal adhesion has to many adaptor proteins because it needs to activate certain things such as
MAPK, Akt, etc. which are downstream signals
- Adaptor proteins of focal adhesion are Talin, FAK, tensin and vinculin
- Adaptor protein for tight junction is ZO-1, and the transmembrane proteins are claudin, occludin,
and JAM
,- Proteins on the apical side cannot cross over to the basal side, and vice versa when a tight junction
is present (tight junction has 4 functions!!)
- In the disease pemphigus, antibodies against desmoglein 3 are created
- Claudin 14 mutation can lead to deafness
- 2 connexons are needed for 1 gap junction, and these can be either big or small, and the half time
of the connexins is pretty small being only a few hours
- Via gap junctions the following can be transported: ca2+, cyclic AMP, nucleotides, amino acids,
small peptides, vitamins (everything smaller than 5k Dalton)
- If neighbouring cell is damaged it can release a high concentration of ca2+ which can cause the
gates to be closed immediately
- Gap junctions in the zona pellucida is important for the development of ovarian follicles
- Which is why a mutation in connexin coding genes leads to infertility
- Autocrine signalling in immunology is important to promote/inhibit cell activation, and fine-tuning
functional responses
- In purinergic signalling ATP is secreted by the cell, and then can either stay the same or turn into
different things and bind to the receptor of the same cell for qualitive or quantitative information
- Adenosine is send by brain cells to the outside and then it binds to the receptors of the same cell,
leading you to have a sense of sleep, caffeine can also bind to this but have no effect
- To much drinking can lead to more receptors being made, which leads to you needing to drink more
coffee to have the same refreshing feeling
- Abruptly stopping with drinking coffee can lead to drowsiness, headaches etc.
- A1 receptor in the heart slows it down, and in the kidney, it filters less blood, leading to less urine in
the bladder (caffeine has the same effect here as in the brain)
- Chemotaxis is also a type of autocrine signalling
,- If neutrophil takes up a bacterial peptide, it can cause production pannexin 1, which leads to
change of cell form, leading to forward migration towards the target that it wants to destroy
Notch:
- Transmembrane notch travels along the cytoplasm until extracellular ligand binding domain touches
notch ligand of another cell
- This leads to Adam-family protease to cut the transmembrane and form the y-secretase complex to
cut it out of the membrane, and let the notch go to the nucleus where it then activates gene
transcription (MAML1 coactivator, and RBPJ transcription factor)
- The notch is then finally ubiquiotaned
- Notch signalling is important for embryonic development, angiogenesis, bone development,
immune system
- In cancer cells the Notch receptor is always turned on, which leads to more proliferation, and
angiogenesis
- Faulty notch signalling can lead to cancer, leukaemia, sclerosis, and Tetralogy of Fallot
- In paracrine signalling the signalling molecules diffuse through extra cellular fluid
- There 4 types: FGF- (RTK), TGF-B-(RTK), wnt-, and hedgehog- pathway
- Learn all the names in the WNT canonical pathway, seen in image case 1
- Segmentation occurs by FGF, Notch, and Wnt
- In the intestinal vili, WNT is pretty high at the low part, but as we get to the upper side, we start to
see it getting lower, and differentiation starts to occur (crypt -> villi)
- If wnt signalling is damaged, then beta catenin can always go to the nucleus, overactivation of
proliferation can lead to cancer
- If sonic hedgehog is not present it leads to inhibition of smoothened (Smo) by patched, which leads
to the phosphorylation and truncation of GLI2/3 to GLI2/3R by CKI, PKA, and GSK3B
- This then translocates to the nucleus and inhibits gene expression
- Patched can get inhibited by shh, which leads to Smo to translocated to the plasma membrane,
leading to GLI2/3 to go to the nucleus, and stimulate gene expression
- Leptin signalling is needed for to body to stop wanting to eat, which can be overturned by fast food
- Neurocrine signalling
, Case 2/3 signalling molecules:
- Secreted molecules: Peptides, proteins, RNA, Gas molecules, lipid derivatives, hormones, ions
- But also, Gastric acid (HCl, KCl, NaCl), Pancreas juice (bicarbonate), mucus (antibacterial enzymes),
surfactant (lipoprotein)
- Sebum (on the hair and skin to keep it flexible, contains lipid derived molecules), saliva (digestive
enzymes), breast milk (protein, carbohydrates, lipids)
- Sweat (NaCl, bacterial nutrient, and pheromones), tears (mixed composition depending on joy or
grieve)
Protein:
- Constitutive pathway is just constantly putting the molecule out of the cell
- While the regulated secretory pathway needs a signal molecule for it to send a molecule outside
(insulin)
- Transporter proteins are on the cell membrane and open and close for proteins and peptides
- Secretory vesicles go to the cell membrane and just fuse and let the inside go to the outside
- Exosomes are first a multivesicular body, and wait on a signal and then release their inside by fusing
with the cell membrane
- Micro vesicle directly bud of from the cell membrane as a whole
- Transmembrane proteins are shaved of by proteases causing the extracellular domain to be cut of
leaving the intracellular domain behind
- The protein can enter the cell easily via easy import, receptor-mediated signal transduction (so
protein with or without vesicle binding to a receptor leads to signal), vesicle fusing with the cell,
vesicle binds to receptor and the inner part or with the vesicle is then imported into the cell
- Insulin (peptide hormone) secretion: glucose gets in glucose transporter -> it turns into ATP leading
to K+ channels to open together with sulphonylurea receptor, leading to ca2+ to come into the cell
leading to insulin secretion because of depolarization
- Insulin goes to muscle/liver from the pancreas (endocrine), where it leads to PI-3K signalling leading
GLUT-4 receptor to bind to the cell membrane where glucose then can enter the cell
- Adipose tissue can secrete 600 types of proteins, and it secretes TNF-a which has inhibitory effect
on insulin which can be found in people with diabetes
- Which is why having too much adipose tissue can lead to health problems
Voordelen van het kopen van samenvattingen bij Stuvia op een rij:
Verzekerd van kwaliteit door reviews
Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!
Snel en makkelijk kopen
Je betaalt supersnel en eenmalig met iDeal, creditcard of Stuvia-tegoed voor de samenvatting. Zonder lidmaatschap.
Focus op de essentie
Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper eminakpulat. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor €0,00. Je zit daarna nergens aan vast.
Is Stuvia te vertrouwen?
4,6 sterren op Google & Trustpilot (+1000 reviews)
Afgelopen 30 dagen zijn er 72042 samenvattingen verkocht
Opgericht in 2010, al 14 jaar dé plek om samenvattingen te kopen