Sequence Analysis of a Subset of Plasma Membrane Raft Proteome Containing CXXC Metal Binding Motifs: Metal Binding Proteins

Abstract

In an attempt to identify the metal sensing proteins localized to mammalian plasma membrane, the authors screened a list of 300 raft associated proteins that are involved in cellular signaling mechanisms by searching the presence of metal thionin CXXC motifs. 50 proteins were found to possess CXXC motifs that could act as potential metal sensing proteins. The authors determined membrane topologies of the above CXXC motif containing proteins using TM-pred and analyzed the positions of their transmembrane TM domains using Bio-edit software. Based on the topology of CXXC domains, the authors classified all the raft-associated metal sensing proteins into six categories. They are i Exoplasmic tails with CXXC motif, ii Exoplasmic loops with CXXC motif, iii Cytosolic tails with CXXC motif, iv Cytosolic loop with CXXC motif, v TM domains with CXXC motifs, vi Proteins with multiple topologies of CXXC motif. The authors' study will lead to understanding of the raft-mediated mechanism of heavy metal sensing and signaling in mammalian cells.