Aim: 

Recently a new group of channel proteins has been discovered, the Pannexins. They have structural similarities to connexins, but appear to be two evolutionary distinct families. We have previously showed that Connexin 43 is located in cardiac mitochondria in addition to the intercalated disc. Our aim was to test if Pannexin 1 is expressed in the heart, and eventually the subcellular location of this protein in cardiac myocytes.

Methods: 

All samples are from Wistar rats. RT-PCR was used to investigate gene expression of Pannexin 1 in liver, heart left ventricle and cultured heart myofibroblasts. Western blotting (WB) and immune-electron microscopy (EM) with 3 different antibodies against Pannexin 1 were used for protein expression. Samples were from left ventricle for EM and from left ventricle, heart myofibroblasts and isolated cardiac mitochondria for WB.

Results: 

Pannexin 1 is expressed in liver, heart and heart myofibroblasts. WB showed that Pannexin 1 was present in isolated cardiac mitochondria. Immune-electron microscopy confirmed mitochondrial location. Pannexin 1 did not seem associated with the cell membrane.

Conclusion: 

Pannexin 1 is expressed in the heart, and probably located to mitochondria and not the cell membrane under normal condition. These findings are important for the understanding of Pannexin 1 function in the heart.