Pyrin-PSTPIP1 colocalises at the leading edge during cell migration.

A set of mutations in the MEditerranean FeVer (MEFV) gene causes familial Mediterranean fever (FMF), the most common auto-inflammatory disease. The gene encodes a protein named pyrin, which appears to play an important role in inflammatory pathways. Furthermore, pyrin, which is expressed in neutrophils, has been reported to interact with proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1) and actin proteins. However, the relations between pyrin and PSTPIP1 during the cell migration have not yet been elucidated. In the present study, we constructed a cell migration assay method using HL-60 cells. Pyrin-PSTPIP1 interactions were analysed by immunofluorescence staining in control, differentiated and differentiated-stimulated HL-60 cells. In stimulated cells, pyrin-polymerised actin, PSTPIP1-polymerised actin and pyrin-PSTPIP1 were found to be colocalised. Pyrin has been shown to be colocalised with actin and PSTPIP1 at the leading edge of the migrating cell. For the first time, PSTPIP1 was found to interact with dynamic actin and pyrin at the site of polarisation.