Antimicrobial RNases in cutaneous defense

Antimicrobial proteins (AMP) are small endogenous proteins which are capable of rapidly inactivating microorganisms at low micro- and nanomolar concentrations. Their significance in host defense is reflected by their wide distribution in nature. Several AMP have been isolated from human skin, and there is increasing evidence that AMP may play an important role in cutaneous defense. One important human AMP class comprises several antimicrobial members of the RNase A superfamily. Of these, two members, RNase 7 and RNase 5, have been implicated in cutaneous defense. This review gives an overview about our current knowledge on the potential role of RNase 7 and RNase 5 in protecting human skin from infection.