perforin1

Perforin1, often shortened to perforin, is a protein encoded by the *PRFN1* gene. It is a key component of the cytotoxic machinery used by immune cells, primarily natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). These immune cells employ perforin to eliminate target cells, such as virus-infected cells or tumor cells, by inducing cell death.

The mechanism involves perforin being released from the granules of these immune cells. Once in the vicinity of a target cell, perforin inserts itself into the target cell's membrane. Multiple perforin molecules then assemble to form pores. These pores allow the passage of other cytotoxic molecules, such as granzymes, into the target cell. Granzymes are a family of serine proteases that trigger apoptosis, or programmed cell death, within the target cell.

Mutations in the *PRFN1* gene can lead to a deficiency in functional perforin. This deficiency impairs the ability of NK cells and CTLs to kill target cells effectively. Consequently, individuals with perforin deficiency are highly susceptible to viral infections, particularly those caused by herpesviruses, and may also experience increased risks of certain cancers. This condition is known as familial hemophagocytic lymphohistiocytosis (FHL), specifically FHL type 2, and other immunodeficiency syndromes. Research into perforin's function is crucial for understanding immune surveillance and developing therapies for immune disorders and cancer.