A hallmark of PKCβ activation is that it is always associated with
translocation of the enzyme from the cytosolic fraction to the cell
particulate fraction, which includes the plasma membrane as well
as many other cellular organelles. Biochemical and imaging studies
have illustrated how multiple lipid-binding modules cooperate to
drive stable membrane localization of PKCβ [11–13]. In general, binding
of DAG provides the energy for displacement of the autoinhibitory
pseudosubstrate from the catalytic cleft, thereby activating the kinase.
The crystal structure of PKCβII provided the first structural glimpse at
how the second messenger DAG activates the kinase [14,15]. It appears
that binding of membrane-embedded DAG to the C1A domain of PKC
forces the pseudosubstrate out of the active site, allowing access to
true substrates. Full activation of PKCβ requires engagement of both
C1 and C2 domains with the membrane, each contributing to activation
in distinct ways (Fig. 1B).