Step 1: Attachment (Lecture 9) Flashcards
What is a receptor?
host-cell surface receptor that a virus takes advantage of for entry (if it has the viral receptor-binding protein for it)
What is a co-receptor?
a second/additional cell-surface molecule required for viral entry
What is host-range?
what is the particular animal/cell that the virus can get into
What is tropism?
refers to the specific cells/tissues that are susceptible and permissive
What makes certain viruses tropic for certain cells?
those cells have the viral receptors on its cell surfaces for these specific viruses
How do viruses adhere to cell surfaces if they are floating?
viruses are attracted to cells due to the electrostatic energy on cell surfaces; this attraction is non-specific = any virus will get attracted
How does the virus find the right receptor to bind to on cell surfaces?
will roll around until it finds a lock and key fit — critical step in establishing infection and more than one receptor may be involved | there needs to be a high number in availability and presence of the viral receptors otherwise ability to infect the cell = very low
What are the 6 properties of viral receptors?
needed for all viruses (except fungi and plants), have a cellular function, can help with entry, moving it around the cell, start signaling cascades; virus of the same family may bind to different receptors, one virus may bind to multiple receptors
Where is heparan sulfate found?
epithelial cells - HPV
What binds to sialic acid?
influenza, RSV, measles, conformation differs between hosts
How do naked virions execute the “key and lock” model in terms of receptor binding?
will have these projections/indentations on its capsid that will bind to the receptors
How do enveloped virions execute the “key and lock” model in terms of receptor binding?
use of integral membrane and ectodomain proteins that will bind to the viral receptors
What is an example of a naked virion?
polio virus
How does polio bind to its viral receptor?
it has indentations on its capsid
What does the CAR receptor stand for? Where is it located?
Coxsackie and Adenovirus Receptor on host cell membrane
