What are the various types of protein-protein interactions
There are so many types of protein-protein interactions via various domains, such as SH2 binding (in RTK signaling), Pleckstrin Homology domain (involved in signaling) among others. This site gives a nice list: http://pawsonlab.mshri.on.ca/index.php?option=com_content&amp;task=view&amp;id=30&amp;Itemid=63

Of course, protein-protein interactions rely on the premises of basic biochemistry:


van-der waals interactions (at the most basic level)
Electrostatic interactions
"Lock and Key" model: Some proteins have specific binding pockets for domains of other proteins
Induced fit


There are many ways to study protein-protein interactions, including, but not limited to


Pull-down assays
2D SDS-PAGE / MS
Yeast two-hybrid
Immunoprecipitation