Pinin (PNN)

PNN protein contains a serine-rich domain; a glutamine-proline, glutamine-leucine repeat domain; an acidic domain rich in glutamic acid; and numerous potential kinase recognition motifs. Northern blot analysis detected ubiquitous expression of PNN in human tissues, including those lacking desmosomes. PNN is expressed as 4.1-, 3.7-, and 3.2-kb transcripts that show tissue-specific expression patterns. Southern blot analysis demonstrated the existence of a single pinin gene in the human genome. Since the 3-prime end of the PNN coding sequence is nearly identical to a partial cDNA identified in a pig neutrophil cDNA library, and since leukocytes, which do not react with antibodies against pinin, express an mRNA that hybridizes with a pinin cDNA, the authors speculated that there may be a pinin-related gene.