Interaction between protein kinase D and components of SUMO conjugation enzyme complex

Abstract

Protein kinase D (PKD) is a serine/threonine protein kinase which is implicated in signaling mechanisms controlling cell proliferation, apoptosis, tumor metastases and immune response. In the previous study we have isolated a clone which could interact with PKD in the yeast twohybrid screen. Sequence analysis has shown that the clone encodes the C-terminal part of small ubiquitin-related modifier (SUMO) activating enzyme Uba2 which together with another activator protein, Aos1, is involved in covalent modification of the target protein by SUMO peptide. Here we show that intracellular Uba2 co-immunoprecipitates with PKD and recombinant GST-Uba2 fusion protein associates with cellular catalitically active PKD. In addition, the recombinant GST-PKD insert fusion protein recruits endogenous Uba2. Data suggest that PKD, by interacting with Uba2, might play a role in the regulation of protein covalent modification with SUMO. Keywords: protein kinase D, SUMO modification complex