I am reading the Handbook of Neurochemistry and Molecular Neurobiology and I am learning about cell adhesion molecules (CAMs) and I have come across the following:
CAMs are involved in homo‐ or heterophilic interactions with molecules positioned on opposing plasma membranes, and such interactions are referred to as trans‐interactions. In addition, CAMs are often involved in homo‐ or heterophilic interactions with other membrane‐associated molecules positioned in the same plasma membrane. Such membrane‐lateral interactions are referred to as cis‐interactions.
I know that cell adhesion molecules are proteins mediation cell-cell or cell-extracellular matrix interactions. However, in the above excerpt from the book in the following statement: CAMs are involved in homo‐ or heterophilic interactions with molecules positioned on opposing plasma membranes, I am not sure what exactly is meant by "opposing plasma membranes". I think that this refers to the plasma membrane of a neighbouring cell the CAM is interacting with, however I am not fully certain. Any insights are appreciated.