Traffic Membranaire 1: Endocytosis Flashcards
Inside the cell, endocytosis will lead to the vesicle formation where the cytoplasmic membrane will :
remain always cytoplasmic whereas the external membrane will be inside the vesicle after endocytosis.
TRUE OR FALSE,
We can modify the external membrane from the vesicle, add sugars and charges
True because the external membrane will be inside the vesicle after endocytosis.
What is the tag for phagocytosis?
During Apoptosis:
The tagged cell will have lost the asymmetry in the cell membrane → PS on the outside → signal for phagocytosis by a macrophage
Pendant l’apoptose, la phosphatidylsérine (PS) devient
exposée au feuillet externe de la membrane plasmique
True or False,
Phagocytosis is actin depended.
TRUE
Pseudopode est dépendant de l’actine
Difference between Macropinocytose and phagocytosis?
Macropinocytose is Similar to phagocytosis but engulfs fluids and nutriments
True or False,
Macropinocytose is actin depended.
TRUE
Polymerization of actin around an activated part of the membrane → via phospholipide PIP3
What does this remind you of?
Polymérisation de l’actine autour d’une région de
membrane “activée” (par la phospholipide PIP3)
Macropinocytose
True or False,
Endocytosis is actin depended.
FALSE
Clathrine dynamine Actin dependent process
facilitée par l’actine et la scission est médiée par la dynamine
ATP dependent process:
Important for the de-polymerization of clathrine
Actin dependent process:
Helps in pushing the membrane to form the vesicle
Clathrine is in form of “triskele” in the cytosol and its polymerization forms the “treillis polyédrale” (less important)
True or False,
Endocytosis is impossible in a clathrin inhibited activity environment.
FALSE
Endocytocis can be using cavéoline:
Very similar to clathrine, but smaller vesicles
cavéoline is commonly found in the radeaux lipidiques
What is special about cavéoline location?
cavéoline is commonly found in the radeaux lipidiques
What are endosomes?
Vésicules entourées d’une simple membrane, qui proviennent de la
membrane plasmique suite à l’endocytose
Explain endosome maturation and pH changes?
Endosome Precoce has high pH. It’s role is moslty recycling and triage
The more the endosomes will mature → the more acidic they become (lower pH; up to pH 5)
Acidity is due to Vacuolar ATPase → V-ATPase → Hydrogen pump: (up to pH5)
Late endosomes and Lysosomes can then exists in a balance
Inside a lysosome there are also a bunch of Hydrolases (proteases) that are only activated in low pH
What are Exosomes?
Extracellular Vesicles released by the cell:
Occurs when Late Endosomes instead of becoming a lysosome merge to the membrane and release the internal vesicles (exosomes)
What is Autophagie?
mécanisme qui entoure en membrane des
régions de cytoplasme, des aggrégats
protéiques, et certaines organites tels que les
mitochondries et les peroxisomes, permettant leur
dégradation via la fusion avec des lysosomes
Les autophagosomes sont formés d’une _____________. Ils
sont formés via l’intermédiares de _________________.
membrane double
phagophore
