Pyrin and Hematopoietic Interferon-Inducible Nuclear Protein Domain Proteins: Innate Immune Sensors for Cytosolic and Nuclear DNA.

Abstract

The innate immune system is the first line of defense against microbial pathogens. The response of innate immunity is initiated by molecules known as pattern recognition receptors (PRRs). Such responses are often triggered by nucleic acids that are delivered to the cytoplasm or nucleus of cells. The ability to recognize foreign nucleic acids in these two locations is an important defense mechanism of the human innate immune system. Several PRRs are located in the cytosol or nucleus and detect foreign DNAs. The pyrin and hematopoietic interferon-inducible nuclear (PYHIN) domain protein is a family of PRRs that includes interferon-inducible protein 16, absent in melanoma 2, PYHIN 1 (or interferon-inducible protein X, as it is also known), myeloid cell nuclear differentiation antigen, and pyrin domain only protein 3. These nuclear and cytosolic sensors play an essential part in host defense of intracellular pathogens. In addition, members of the PYHIN family are critical regulators of immune response, apoptosis, cell growth, differentiation, and transcription. In this review, we summarize important characteristics of these innate immune sensors and their roles in several diseases. A better understanding of the role of DNA sensors in the nucleus and cytoplasm will lead to the development of novel therapeutic approaches to control infections and associated diseases.