Dr. Russell investigates the role of the type IV intermediate filament (IF) protein synemin as an A-kinase anchoring protein (AKAP) in cardiac myocytes. AKAPs act to anchor PKA near substrates and thus aid in specificity of this signaling pathway. Numerous AKAPs have also been recognized as multivalent scaffold proteins, binding both activators and inhibitors of the PKA pathway and also other signaling proteins. In this way, at least some AKAPs act as sites of cross-talk.
Synemin is expressed in at least two isoforms in myocytes, with the larger isoform (a-synemin) containing a 312 amino acid insert near the C-terminus of its long tail domain. We believe that each synemin isoform plays a different role in signal transduction. This is based on the fact that each has an identical head and rod domain, the regions necessary for formation of IFs. The unusually long C-terminal tails of the type IV IF proteins are predicted to function in cell signaling and is the location of the 312 amino acid insert that differentiates the two synemin isoforms. Each isoform does contain the PKA binding region and thus functions as an AKAP.
With an eye towards elucidating the purpose of having two isoforms expressed in the same cell type, Dr. Russell has recently initiated several lines of study that have resulted in peer-reviewed publications and national grant submissions.
Anyone who is interested in participating in these studies, either as a member of the lab or a collaborator, is encouraged to contact Dr. Russell.