Article

A mechanism for the evolution of phosphorylation sites.

Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
Cell (Impact Factor: 33.12). 11/2011; 147(4):934-46. DOI: 10.1016/j.cell.2011.08.052
Source: PubMed

ABSTRACT Protein phosphorylation provides a mechanism for the rapid, reversible control of protein function. Phosphorylation adds negative charge to amino acid side chains, and negatively charged amino acids (Asp/Glu) can sometimes mimic the phosphorylated state of a protein. Using a comparative genomics approach, we show that nature also employs this trick in reverse by evolving serine, threonine, and tyrosine phosphorylation sites from Asp/Glu residues. Structures of three proteins where phosphosites evolved from acidic residues (DNA topoisomerase II, enolase, and C-Raf) show that the relevant acidic residues are present in salt bridges with conserved basic residues, and that phosphorylation has the potential to conditionally restore the salt bridges. The evolution of phosphorylation sites from glutamate and aspartate provides a rationale for why phosphorylation sometimes activates proteins, and helps explain the origins of this important and complex process.

Download full-text

Full-text

Available from: Samuel Mark Pearlman, Nov 19, 2014
0 Followers
 · 
153 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this review we address some recent developments in the field of bacterial protein phosphorylation, focusing specifically on serine/threonine and tyrosine kinases. We present an overview of recent studies outlining the scope of physiological processes that are regulated by phosphorylation, ranging from cell cycle, growth, cell morphology, to metabolism, developmental phenomena and virulence. Specific emphasis is placed on Mycobacterium tuberculosis as a showcase organism for serine/threonine kinases, and Bacillus subtilis to illustrate the importance of protein phosphorylation in developmental processes. We argue that bacterial serine/threonine and tyrosine kinases have a distinctive feature of phosphorylating multiple substrates, and might thus represent integration nodes in the signaling network. Some open questions regarding the evolutionary benefits of relaxed substrate selectivity of these kinases are treated, as well as the notion of non-functional "background" phosphorylation of cellular proteins. We also argue that phosphorylation events for which an immediate regulatory effect is not clearly established should not be dismissed as unimportant, as they may have a role in cross-talk with other post-translational modifications. Finally, recently developed methods for studying protein phosphorylation networks in bacteria are briefly discussed. This article is protected by copyright. All rights reserved.
    FEMS Microbiology Letters 06/2013; 346(1). DOI:10.1111/1574-6968.12189 · 2.72 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A mechanistic understanding of signaling networks requires identification and analysis of phosphorylation sites. Mass spectrometry offers a rapid and highly sensitive approach to mapping phosphorylation sites. However, mass spectrometry has significant limitations that must be considered when planning to carry out phosphorylation-site mapping. Here we provide an overview of key information that should be taken into consideration before beginning phosphorylation-site analysis, as well as a step-by-step guide for carrying out successful experiments.
    Molecular biology of the cell 03/2013; 24(5):535-42. DOI:10.1091/mbc.E12-09-0677 · 5.98 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The kinetochore forms a dynamic interface with micro-tubules from the mitotic spindle during mitosis. The Ndc80 complex acts as the key microtubule-binding com-plex at kinetochores. However, it is unclear how the Ndc80 complex associates with the inner kinetochore proteins that assemble upon centromeric chromatin. Here, based on a high-resolution structural analysis, we demonstrate that the N-terminal region of vertebrate CENP-T interacts with the 'RWD' domain in the Spc24/25 portion of the Ndc80 complex. Phosphorylation of CENP-T strengthens a cryptic hydrophobic interaction between CENP-T and Spc25 resulting in a phospho-regulated interaction that occurs without direct recognition of the phosphorylated residue. The Ndc80 complex interacts with both CENP-T and the Mis12 complex, but we find that these interactions are mutually exclusive, supporting a model in which two distinct pathways target the Ndc80 complex to kineto-chores. Our results provide a model for how the multiple protein complexes at kinetochores associate in a phospho-regulated manner. The EMBO Journal advance online publication, 18 January 2013; doi:10.1038/emboj.2012.348
    The EMBO Journal 01/2013; DOI:10.1038/emboj.2012.348 · 10.75 Impact Factor