Expression of Parkin Isoforms in Human Lymphomonocyte

Parkin (PARK2) is one of the largest gene of the human genome. Its mutations cause a form of autosomal recessive juvenile-onset of Parkinson disease (ARJPD) (1). To date, have been identified 21 parkin alternative splice variants. However most of the studies have focused their attention exclusively on full-length protein. The expression of parkin was also assessed in human blood (2, 3), however, until now, no study has determined expression profile of parkin isoforms in human lymphomonocyte (LMN). In the present study, we have investigated for the first time, the expression of parkin isoforms in three LMN subpopulations such as T lymphocyte (CD2+), monocyte (CD14+) and B lymphocyte (CD19+). The expression of H1/H5 and H6 isoforms has been observed in total LMN homogenate , whereas H20 and H1/H5 variants were detected in all three LMN subpopulations by western blot analysis. The distribution of parkin isoforms has also been evaluated by immunofluorescence analysis. Although parkin is predominantly expressed in the cytoplasm, immunoreactivity has also been detected at nuclear and perinuclear level. Our data suggest that the analysis of the expression of these isoforms on LMN of ARJP patients might allow to identify a specific expression profile of parkin isoforms helpful for the diagnosis of this neurodegenerative disease.