Problem:

I know that quaternary protein structures are formed exclusively via non-covalent bonds. My biochemistry professor discussed a viral capsid that is essentially one quaternary structure with 240 individual monomers of 4 kinds. I suspect that for this protein coat to be stable, the non-covalent bonds holding it together must be rather stable. He also mentioned that different monomers can join to form the functional protein complex from relatively far distances, like across an entire cell, which once again leads me to believe that both monomers must be interacting with each other very strongly.

Question: Since a strong non-covalent interaction is required between (at least) two protein monomers to form the functional quaternary structure, can one particular protein be a monomer to an array of different quaternary complexes?

Question: Are there any examples of this? If yes then explain it with the help of example.