Immunocytochemical and immunohistochemical application of monoclonal antibodies against peroxisomal biogenesis factor 14

PEX14 is an integral membrane protein essential for protein docking onto the peroxisomes and is a bi-functional protein capable of acting as a transcriptional co-repressor and a polypeptide transport modulator. Further studies showed that PEX14 is the sole peroxin that has a unique dual function in peroxisome formation and selective degradation. Its RNA transcripts are ubiquitously expressed; there is, however, no data on the expression profiles of PEX14 at the protein level due to a lack of MAbs suitable for immunohistochemical staining, thus hindering studies on its functions. In the present study, we generated one MAb that could be used in immunocytochemistry and immunohistochemistry and investigated PEX14 expression in normal and malignant human tissues. In contrast to the ubiquitous expression of its RNA transcripts, there is no PEX14 protein expression in normal human tissue, including liver, spleen, lung, rectum, brain, prostate, breast, ovary, and stomach. Protein expression of PEX14 was dramatically upregulated in some malignancies. Presented here are the first data on the expression profiles of PEX14 at the protein level, which will further our understanding of its functions.