Virusziekten samenvatting HC.7
Membrane function is a key process in cellular life. You have three kinds of membrane
fusion:
1. Intracellular fusion
Cell secretory pathway
ER to Golgi and back
Golgi to plasma membrane and back
Synaptic transmission
Organelle fusion
Mitochondrial fusion
Endosome-lysosome fusion
Mostly mediated by SNAREs.
2. Cell-Cell fusion
3. Fusion of virus membrane with host cell membrane
Enveloped viruses needs to fuse their membrane with that of the host to deliver the
viral content
Mediated by viral fusion proteins
There are different routes of virus entry. But there are two common things in every entry:
attachment and crossing the host membrane. In all cases, and all steps of the viral entry are
mediated by specialized proteins!!
Attachment is mediated by virion protein(s) binding to specific host surface
molecule(s) such as membrane proteins, lipids or the carbohydrate moieties present either
on glycoproteins or glycolipis.
Crossing the host membrane
, Pore-mediated entry
Lysis or membrane permeabilization (many non-enveloped viruses)
Membrane fusion (enveloped viruses)
Biolayer piophysics
The intrinsic tendency of a lipid bilayer is to adapt and keep a flat shape (some lipids
spontaneously form monolayers of different curvatures)
In the lipid bilayer the two monolayers will tend, energetically, to have the same lipid
composition
The bilayer will be completely symmetric with respect to its mid plane
Bilayer will oppose curving by external forces
Membrane function is a key process in cellular life. You have three kinds of membrane
fusion:
1. Intracellular fusion
Cell secretory pathway
ER to Golgi and back
Golgi to plasma membrane and back
Synaptic transmission
Organelle fusion
Mitochondrial fusion
Endosome-lysosome fusion
Mostly mediated by SNAREs.
2. Cell-Cell fusion
3. Fusion of virus membrane with host cell membrane
Enveloped viruses needs to fuse their membrane with that of the host to deliver the
viral content
Mediated by viral fusion proteins
There are different routes of virus entry. But there are two common things in every entry:
attachment and crossing the host membrane. In all cases, and all steps of the viral entry are
mediated by specialized proteins!!
Attachment is mediated by virion protein(s) binding to specific host surface
molecule(s) such as membrane proteins, lipids or the carbohydrate moieties present either
on glycoproteins or glycolipis.
Crossing the host membrane
, Pore-mediated entry
Lysis or membrane permeabilization (many non-enveloped viruses)
Membrane fusion (enveloped viruses)
Biolayer piophysics
The intrinsic tendency of a lipid bilayer is to adapt and keep a flat shape (some lipids
spontaneously form monolayers of different curvatures)
In the lipid bilayer the two monolayers will tend, energetically, to have the same lipid
composition
The bilayer will be completely symmetric with respect to its mid plane
Bilayer will oppose curving by external forces
