RESUMO
Years of evolution have kept actin conserved throughout various clades of life. It is an essential protein starring in many cellular processes. In a primitive eukaryote named Entamoeba histolytica, actin directs the process of phagocytosis. A finely tuned coordination between various actin-binding proteins (ABPs) choreographs this process and forms one of the virulence factors for this protist pathogen. The ever-expanding world of ABPs always has space to accommodate new and varied types of proteins to the earlier existing repertoire. In this article, we report the identification of 390 ABPs from Entamoeba histolytica. These proteins are part of diverse families that have been known to regulate actin dynamics. Most of the proteins are primarily uncharacterized in this organism; however, this study aims to annotate the ABPs based on their domain arrangements. A unique characteristic about some of the ABPs found is the combination of domains present in them unlike any other reported till date. Calponin domain-containing proteins formed the largest group among all types with 38 proteins, followed by 29 proteins with the infamous BAR domain in them, and 23 proteins belonging to actin-related proteins. The other protein families had a lesser number of members. Presence of exclusive domain arrangements in these proteins could guide us to yet unknown actin regulatory mechanisms prevalent in nature. This article is the first step to unraveling them.
Assuntos
Citoesqueleto de Actina/genética , Actinas/genética , Proteínas de Ligação ao Cálcio/genética , Entamoeba histolytica/genética , Proteínas dos Microfilamentos/genética , Proteínas de Protozoários/genética , Citoesqueleto de Actina/química , Citoesqueleto de Actina/metabolismo , Actinas/classificação , Actinas/metabolismo , Sequência de Aminoácidos , Proteínas de Ligação ao Cálcio/metabolismo , Bases de Dados de Proteínas , Entamoeba histolytica/classificação , Entamoeba histolytica/metabolismo , Entamoeba histolytica/patogenicidade , Forminas/classificação , Forminas/genética , Forminas/metabolismo , Expressão Gênica , Proteínas dos Microfilamentos/classificação , Proteínas dos Microfilamentos/metabolismo , Anotação de Sequência Molecular , Família Multigênica , Fagocitose/fisiologia , Filogenia , Profilinas/classificação , Profilinas/genética , Profilinas/metabolismo , Isoformas de Proteínas/classificação , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas de Protozoários/classificação , Proteínas de Protozoários/metabolismo , Fatores de Virulência/classificação , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , CalponinasRESUMO
An extensive polymorphism analysis of pollen profilin, a fundamental regulator of the actin cytoskeleton dynamics, has been performed with a major focus in 3D-folding maintenance, changes in the 2-D structural elements, surface residues involved in ligands-profilin interactions and functionality, and the generation of conformational and lineal B- and T-cell epitopes variability. Our results revealed that while the general fold is conserved among profilins, substantial structural differences were found, particularly affecting the special distribution and length of different 2-D structural elements (i.e. cysteine residues), characteristic loops and coils, and numerous micro-heterogeneities present in fundamental residues directly involved in the interacting motifs, and to some extension these residues nearby to the ligand-interacting areas. Differential changes as result of polymorphism might contribute to generate functional variability among the plethora of profilin isoforms present in the olive pollen from different genetic background (olive cultivars), and between plant species, since biochemical interacting properties and binding affinities to natural ligands may be affected, particularly the interactions with different actin isoforms and phosphoinositides lipids species. Furthermore, conspicuous variability in lineal and conformational epitopes was found between profilins belonging to the same olive cultivar, and among different cultivars as direct implication of sequences polymorphism. The variability of the residues taking part of IgE-binding epitopes might be the final responsible of the differences in cross-reactivity among olive pollen cultivars, among pollen and plant-derived food allergens, as well as between distantly related pollen species, leading to a variable range of allergy reactions among atopic patients. Identification and analysis of commonly shared and specific epitopes in profilin isoforms is essential to gain knowledge about the interacting surface of these epitopes, and for a better understanding of immune responses, helping design and development of rational and effective immunotherapy strategies for the treatment of allergy diseases.
Assuntos
Antígenos de Plantas/química , Epitopos de Linfócito B/química , Epitopos de Linfócito T/química , Proteínas de Plantas/química , Pólen/química , Profilinas/química , Sequência de Aminoácidos , Epitopos de Linfócito B/classificação , Epitopos de Linfócito B/genética , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito T/classificação , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Hipersensibilidade Alimentar/imunologia , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Olea/química , Filogenia , Polimorfismo Genético/imunologia , Profilinas/classificação , Profilinas/genética , Profilinas/imunologia , Estrutura Terciária de Proteína , Alinhamento de Sequência , Homologia Estrutural de ProteínaRESUMO
We isolated and characterized the profilin (FcPFN) cDNA from hemocytes of Fenneropenaeus chinensis, a unique shrimp species from the Yellow Sea. The FcPFN cDNA consists of 830 bp and encodes a polypeptide of 125 amino acids, having a predicted isoelectric point of 5.06. The deduced amino acid sequence of FcPFN shows 36% and 90% amino acid sequence identity to the profilin genes of Pacific white shrimp Litopenaeus vannamei and black tiger shrimp Penaeus monodon, respectively. The FcPFN mRNA was highly expressed in hemocytes and hepatopancreas and moderately in muscle of normal shrimp. The higher expression of FcPFN mRNA is observed in shrimp infected with the white spot syndrome virus (WSSV), which is a major concern in all shrimp-growing regions of the world. These results suggest a potential role for FcPFN in viral host defense mechanisms.
Assuntos
Penaeidae/genética , Penaeidae/virologia , Profilinas/genética , Vírus da Síndrome da Mancha Branca 1 , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Hemócitos/metabolismo , Hemócitos/virologia , Dados de Sequência Molecular , Filogenia , Profilinas/química , Profilinas/classificação , Alinhamento de SequênciaRESUMO
The three dimensional structures of profilins from invertebrates and vertebrates are remarkably similar despite low sequence similarity. Their evolutionary relationship remains thus enigmatic. A phylogenetic analysis of profilins from Deuterostoma indicates that profilin III and IV isoforms each form distinct groups. Profilin IV is most related to invertebrate profilins and originated prior to vertebrate evolution whereas separation of profilin I, II and III isoforms occurred early in vertebrate evolution. Viral profilins are most similar to profilin III. In silico analysis of representative profilin gene structures corroborates the phylogenetic result and we discuss this in terms of biochemical differences.
