title: Sequence and comparative genomic analysis of actin-related proteins.
abstract: Actin-related proteins (ARPs) are key players in cytoskeleton activities and nuclear functions. Two complexes, ARP2/3 and ARP1/11, also known as dynactin, are implicated in actin dynamics and in microtubule-based trafficking, respectively. ARP4 to ARP9 are components of many chromatin-modulating complexes. Conventional actins and ARPs codefine a large family of homologous proteins, the actin superfamily, with a tertiary structure known as the actin fold. Because ARPs and actin share high sequence conservation, clear family definition requires distinct features to easily and systematically identify each subfamily. In this study we performed an in depth sequence and comparative genomic analysis of ARP subfamilies. A high-quality multiple alignment of approximately 700 complete protein sequences homologous to actin, including 148 ARP sequences, allowed us to extend the ARP classification to new organisms. Sequence alignments revealed conserved residues, motifs, and inserted sequence signatures to define each ARP subfamily. These discriminative characteristics allowed us to develop ARPAnno (http://bips.u-strasbg.fr/ARPAnno), a new web server dedicated to the annotation of ARP sequences. Analyses of sequence conservation among actins and ARPs highlight part of the actin fold and suggest interactions between ARPs and actin-binding proteins. Finally, analysis of ARP distribution across eukaryotic phyla emphasizes the central importance of nuclear ARPs, particularly the multifunctional ARP4.
authors.affiliation: Laboratoire de Biologie et Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, BP 163, 67404 Illkirch Cedex, France. jean.muller@igbmc.u-strasbg.fr
authors.forename: Jean
authors.initials: J
authors.lastname: Muller
authors.forename: Yukako
authors.initials: Y
authors.lastname: Oma
authors.forename: Laurent
authors.initials: L
authors.lastname: Vallar
authors.forename: Evelyne
authors.initials: E
authors.lastname: Friederich
authors.forename: Olivier
authors.initials: O
authors.lastname: Poch
authors.forename: Barbara
authors.initials: B
authors.lastname: Winsor
mesh_terms: D000199:Actins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D017124:Conserved Sequence; D016678:Genome; D020407:Internet; D051379:Mice; D008958:Models, Molecular; D016254:Mutagenesis, Insertional; D009693:Nucleic Acid Hybridization / Q000379:methods; D010802:Phylogeny; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017384:Sequence Deletion
chemical_list: D000199:Actins