USH and FOG2 are able to inhibit PI3K activity through direct interaction with its regulatory subunits, dp60 and p85α respectively. This prevents the formation of an active PI3K complex.
Certain proteins, such as USH and FOG2, are able to prevent the activation of PI3K by physically binding to its regulatory components, dp60 and p85α. As a result, the formation of an active PI3K complex is hindered in specific contexts.