Holds between molecular entities A and B where A can physically interact with B and in doing so regulates a process that B is capable of. For example, A and B may be gene products and binding of B by A regulates the kinase activity of B.

The entity A, immediately upstream of the entity B, has an activity that regulates an activity performed by B. For example, A and B may be gene products and binding of B by A regulates the kinase activity of B. A and B can be physically interacting but not necessarily. Immediately upstream means there are no intermediate entity between A and B.

Synonyms: molecularly controls