Perforin: A key pore-forming protein for immune control of viruses and cancer

Abstract

Perforin (PFN) is the key pore-forming molecule in the cytotoxic granules of immune killer cells. Expressed only in killer cells, PFN is the ratelimiting molecule for cytotoxic function, delivering the death-inducing granule serine proteases (granzymes) into target cells marked for immune elimination. In this chapter we describe our current understanding of how PFN accomplishes this task. We discuss where PFN is expressed and how its expression is regulated, the biogenesis and storage of PFN in killer cells and how they are protected from potential damage, how it is released, how it delivers Granzymes into target cells and the consequences of PFN deficiency.