The Cdk-like protein PCTAIRE-1 from mouse brain associates with p11 and 14-3-3 proteins

PCTAIRE-1 is a member of the cyclin-dependent kinase (cdk)-like class of proteins, and is localized mainly in the mammalian brain. Using the yeast two-hybrid system we screened a mouse brain cDNA library with PCTAIRE-1 as bait, and isolated several clones coding for the mouse homologs of the following proteins: p11 (also known as calpactin I light chain) and the eta, theta (also known as tau) and zeta isoforms of 14-3-3 proteins. We confirmed that these four proteins interact with PCTAIRE-1 by demonstrating the biochemical interactions using the pure recombinant proteins. The fact that 14-3-3 proteins are known to interact with many other intracellular proteins (such as C-kinase, Raf, Bcr, P13-kinase) and p11 with annexin II (a major pp60(v-src) and C-kinase substrate) suggests that PCTAIRE-1 might be part of multiple signal transduction cascades and cellular protein networks.