title: Phosphatidylinositol transfer proteins: sequence motifs in structural and evolutionary analyses.
abstract: Phosphatidylinositol transfer proteins (PITP) are a family of monomeric proteins that bind and transfer phosphatidylinositol and phosphatidylcholine between membrane compartments. They are required for production of inositol and diacylglycerol second messengers, and are found in most metazoan organisms. While PITPs are known to carry out crucial cell-signaling roles in many organisms, the structure, function and evolution of the majority of family members remains unexplored; primarily because the ubiquity and diversity of the family thwarts traditional methods of global alignment. To surmount this obstacle, we instead took a novel approach, using MEME and a parsimony-based analysis to create a cladogram of conserved sequence motifs in 56 PITP family proteins from 26 species. In keeping with previous functional annotations, three clades were supported within our evolutionary analysis; two classes of soluble proteins and a class of membrane-associated proteins. By, focusing on conserved regions, the analysis allowed for in depth queries regarding possible functional roles of PITP proteins in both intra- and extra- cellular signaling.
authors.affiliation: Division of Molecular Biology and Biochemistry, University of Missouri-Kansas City, Kansas City, USA.
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Wyckoff
authors.affiliation: Vassa Informatics, Kansas City, USA.
authors.forename: Ada
authors.initials: A
authors.lastname: Solidar
authors.affiliation: Division of Cell Biology and Biophysics, University of Missouri-Kansas City, Kansas City, USA. wyckoffg@umkc.edu.
authors.forename: Marilyn D
authors.initials: MD
authors.lastname: Yoden
keywords: Phylogenetics; Protein Evolution; Sequence Motif; Structural Domain