Figure 3.

A current model for the complex formed by KRAB-containing proteins and other proteins. A KRAB-containing protein binds specifically to a gene promoter through its multiple zinc fingers. A trimeric Kap1 complex binds to the KRAB domain of the KRAB-containing protein and serves as a scaffold for recruitment of HP1, HDACs, and Setdb1, to form heterochromatin. Note that the figure does not include the SCAN domain because, apart from its ability to dimerize, the role of this domain remains poorly understood.