Pannexin channels: the emerging therapeutic targets.

Intercellular communication plays a pivotal role in various physiological functions. This is mainly done through gap junctions and trans-membrane channels. The structural proteins forming these channels are different in vertebrates and invertebrates namely connexins and innexins respectively. Recently, a new class of proteins playing a crucial role in intercellular communication was discovered and named pannexins. They are found to have similar homology to innexins. Earlier they were also thought to form gap junctions and hemi channels on oppositional cell surfaces like connexins but later they were found to have different structure, location and function than connexins. Their main role is in the initiation and propagation of cellular calcium waves and ATP release. They are also considered an integral part of the greater purinergic and adrenergic receptor complexes. They are implicated in wide variety of biochemical and pathophysiological functions ranging from apoptosis, inflammation, ischemia, seizures and immune response; to paracrine signaling, vasodymanics, tumor genesis, cellular differentiation and development. Due to their ubiquitous distribution and involvement in myriad cellular functions, they are considered as potential therapeutic targets for diseases like hypertension, epilepsy and immune disorders.