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1.
Mol Biol Evol ; 31(8): 2181-93, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24895411

RESUMEN

Vitellogenin (Vg), a storage protein, has been extensively studied for its egg-yolk precursor role, and it has been suggested to be fundamentally involved in caste differences in social insects. More than one Vg copy has been reported in several oviparous species, including ants. However, the number and function of different Vgs, their phylogenetic relatedness, and their role in reproductive queens and nonreproductive workers have been studied in few species only. We studied caste-biased expression of Vgs in seven Formica ant species. Only one copy of conventional Vg was identified in Formica species, and three Vg homologs, derived from ancient duplications, which represent yet undiscovered Vg-like genes. We show that each of these Vg-like genes is present in all studied Hymenoptera and some of them in other insects as well. We show that after each major duplication event, at least one of the Vg-like genes has experienced a period of positive selection. This, combined with the observation that the Vg-like genes have acquired or lost specific protein domains suggests sub- or neofunctionalization between Vg and the duplicated genes. In contrast to earlier studies, Vg was not consistently queen biased in its expression, and the caste bias of the three Vg-like genes was highly variable among species. Furthermore, a truncated and Hymenoptera-specific Vg-like gene, Vg-like-C, was consistently worker biased. Multispecies comparisons are essential for Vg expression studies, and for gene expression studies in general, as we show that expression and also, putative functions cannot be generalized even among closely related species.


Asunto(s)
Hormigas/clasificación , Hormigas/metabolismo , Proteínas de Insectos/genética , Vitelogeninas/genética , Animales , Evolución Molecular , Femenino , Duplicación de Gen , Proteínas de Insectos/química , Proteínas de Insectos/metabolismo , Masculino , Modelos Moleculares , Filogenia , Conformación Proteica , Estructura Secundaria de Proteína , Selección Genética , Homología de Secuencia , Vitelogeninas/química , Vitelogeninas/metabolismo
2.
J Biol Chem ; 288(39): 28369-81, 2013 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-23897804

RESUMEN

Large lipid transfer proteins are involved in lipid transportation and diverse other molecular processes. These serum proteins include vitellogenins, which are egg yolk precursors and pathogen pattern recognition receptors, and apolipoprotein B, which is an anti-inflammatory cholesterol carrier. In the honey bee, vitellogenin acts as an antioxidant, and elevated vitellogenin titer is linked to prolonged life span in this animal. Here, we show that vitellogenin has cell and membrane binding activity and that it binds preferentially to dead and damaged cells. Vitellogenin binds directly to phosphatidylcholine liposomes and with higher affinity to liposomes containing phosphatidylserine, a lipid of the inner leaflet of cell membranes that is exposed in damaged cells. Vitellogenin binding to live cells, furthermore, improves cell oxidative stress tolerance. This study can shed more light on why large lipid transfer proteins have a well conserved α-helical domain, because we locate the lipid bilayer-binding ability of vitellogenin largely to this region. We suggest that recognition of cell damage and oxidation shield properties are two mechanisms that allow vitellogenin to extend honey bee life span.


Asunto(s)
Antioxidantes/metabolismo , Abejas/citología , Membrana Celular/metabolismo , Estrés Oxidativo , Especies Reactivas de Oxígeno , Vitelogeninas/metabolismo , Secuencia de Aminoácidos , Animales , Muerte Celular , Separación Celular , Citometría de Flujo , Membrana Dobles de Lípidos/metabolismo , Liposomas/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Filogenia , Estructura Secundaria de Proteína , Células Sf9
3.
J Exp Biol ; 215(Pt 11): 1837-46, 2012 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-22573762

RESUMEN

Vitellogenin (Vg) is an egg-yolk precursor protein in most oviparous species. In honeybee (Apis mellifera), the protein (AmVg) also affects social behavior and life-span plasticity. Despite its manifold functions, the AmVg molecule remains poorly understood. The subject of our structure-oriented AmVg study is its polyserine tract - a little-investigated repetitive protein segment mostly found in insects. We previously reported that AmVg is tissue specifically cleaved in the vicinity of this tract. Here, we show that, despite its potential for an open, disordered structure, AmVg is unexpectedly resistant to trypsin/chymotrypsin digestion at the tract. Our findings suggest that multiple phosphorylation plays a role in this resilience. Sequence variation is highly pronounced at the polyserine region in insect Vgs. We demonstrate that sequence differences in this region can lead to structural variation, as NMR and circular dichroism (CD) evidence assign different conformational propensities to polyserine peptides from the honeybee and the jewel wasp Nasonia vitripennis; the former is extended and disordered and the latter more compact and helical. CD analysis of the polyserine region of bumblebee Bombus ignitus and wasp Pimpla nipponica supports a random coil structure in these species. The spectroscopic results strengthen our model of the AmVg polyserine tract as a flexible domain linker shielded by phosphorylation.


Asunto(s)
Vitelogeninas/química , Secuencia de Aminoácidos , Animales , Abejas/genética , Abejas/metabolismo , Sitios de Unión , Modelos Moleculares , Datos de Secuencia Molecular , Resonancia Magnética Nuclear Biomolecular , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/metabolismo , Péptidos/química , Fosforilación , Conformación Proteica , Proteolisis , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homología de Secuencia de Aminoácido , Electricidad Estática , Espectrometría de Masas en Tándem , Vitelogeninas/genética , Vitelogeninas/metabolismo , Avispas/genética , Avispas/metabolismo
4.
Mol Ecol ; 20(24): 5111-3, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22250301

RESUMEN

In this issue of Molecular Ecology, Kent et al. (2011) describe the adaptive evolution of honey bee vitellogenin that belongs to a phylogenetically conserved group of egg yolk precursors. This glyco-lipoprotein leads a double life: it is central to egg production in the reproductive queen caste, and a regulator of social behaviour in the sterile worker caste. Does such social pleiotropy constrain molecular evolution? To the contrary; Kent et al. show that the vitellogenin gene is under strong positive selection in honey bees. Rapid change has taken place in specific protein regions, shedding light on the evolution of novel vitellogenin functions.


Asunto(s)
Adaptación Biológica/genética , Abejas/genética , Evolución Biológica , Vitelogeninas/genética , Animales , Femenino
5.
J Exp Biol ; 214(Pt 4): 582-92, 2011 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-21270306

RESUMEN

Vitellogenin, an egg-yolk protein precursor common to oviparous animals, is found abundantly in honeybee workers - a caste of helpers that do not usually lay eggs. Instead, honeybee vitellogenin (180 kDa) participates in processes other than reproduction: it influences hormone signaling, food-related behavior, immunity, stress resistance and longevity. The molecular basis of these functions is largely unknown. Here, we establish and compare the molecular properties of vitellogenin from honeybee hemolymph (blood) and abdominal fat body, two compartments that are linked to vitellogenin functions. Our results reveal a novel 40 kDa vitellogenin fragment in abdominal fat body tissue, the main site for vitellogenin synthesis and storage. Using MALDI-TOF combined with MS/MS mass-spectroscopy, we assign the 40 kDa fragment to the N terminus of vitellogenin, whereas a previously observed 150 kDa fragment corresponded to the remainder of the protein. We show that both protein units are N glycosylated and phosphorylated. Focusing on the novel 40 kDa fragment, we present a homology model based on the structure of lamprey lipovitellin that includes a conserved ß-barrel-like shape, with a lipophilic cavity in the interior and two insect-specific loops that have not been described before. Our data indicate that the honeybee fat body vitellogenin experiences cleavage unlike hemolymph vitellogenin, a pattern that can suggest a tissue-specific role. Our experiments advance the molecular understanding of vitellogenin, of which the multiple physiological and behavioral effects in honeybees are well established.


Asunto(s)
Abejas/química , Modelos Moleculares , Vitelogeninas/sangre , Vitelogeninas/química , Animales , Secuencia de Bases , Cuerpo Adiposo/química , Femenino , Técnica del Anticuerpo Fluorescente , Hemolinfa/química , Modelos Genéticos , Análisis de Secuencia de ADN , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrometría de Masas en Tándem , Vitelogeninas/genética
6.
BMC Cell Biol ; 10: 22, 2009 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-19327143

RESUMEN

BACKGROUND: The PDZ-LIM proteins are a family of signalling adaptors that interact with the actin cross-linking protein, alpha-actinin, via their PDZ domains or via internal regions between the PDZ and LIM domains. Three of the PDZ-LIM proteins have a conserved 26-residue ZM motif in the internal region, but the structure of the internal region is unknown. RESULTS: In this study, using circular dichroism and nuclear magnetic resonance (NMR), we showed that the ALP internal region (residues 107-273) was largely unfolded in solution, but was able to interact with the alpha-actinin rod domain in vitro, and to co-localize with alpha-actinin on stress fibres in vivo. NMR analysis revealed that the titration of ALP with the alpha-actinin rod domain induces stabilization of ALP. A synthetic peptide (residues 175-196) that contained the N-terminal half of the ZM motif was found to interact directly with the alpha-actinin rod domain in surface plasmon resonance (SPR) measurements. Short deletions at or before the ZM motif abrogated the localization of ALP to actin stress fibres. CONCLUSION: The internal region of ALP appeared to be largely unstructured but functional. The ZM motif defined part of the interaction surface between ALP and the alpha-actinin rod domain.


Asunto(s)
Actinina/química , Proteínas de Microfilamentos/química , Actinina/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Línea Celular Tumoral , Colorantes Fluorescentes/química , Humanos , Proteínas con Dominio LIM , Proteínas de Microfilamentos/biosíntesis , Proteínas de Microfilamentos/metabolismo , Datos de Secuencia Molecular , Péptidos/síntesis química , Péptidos/metabolismo , Unión Proteica , Estructura Terciaria de Proteína , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Resonancia por Plasmón de Superficie
7.
PLoS One ; 8(5): e63688, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23723994

RESUMEN

Insect chemical communication and chemosensory systems rely on proteins coded by several gene families. Here, we have combined protein modeling with evolutionary analysis in order to study the evolution and structure of chemosensory proteins (CSPs) within arthropods and, more specifically, in ants by using the data available from sequenced genomes. Ants and other social insects are especially interesting model systems for the study of chemosensation, as they communicate in a highly complex social context and much of their communication relies on chemicals. Our ant protein models show how this complexity has shaped CSP evolution; the proteins are highly modifiable by their size, surface charge and binding pocket. Based on these findings, we divide ant CSPs into three groups: typical insect CSPs, an ancient 5-helical CSP and hymenopteran CSPs with a small binding pocket, and suggest that these groups likely serve different functions. The hymenopteran CSPs have duplicated repeatedly in individual ant lineages. In these CSPs, positive selection has driven surface charge changes, an observation which has possible implications for the interaction between CSPs and ligands or odorant receptors. Our phylogenetic analysis shows that within the Arthropoda the only highly conserved gene is the ancient 5-helical CSP, which is likely involved in an essential ubiquitous function rather than chemosensation. During insect evolution, the 6-helical CSPs have diverged and perform chemosensory functions among others. Our results contribute to the general knowledge of the structural differences between proteins underlying chemosensation and highlight those protein properties which have been affected by adaptive evolution.


Asunto(s)
Hormigas/genética , Evolución Molecular , Proteínas de Insectos/química , Proteínas de Insectos/genética , Modelos Moleculares , Familia de Multigenes , Homología Estructural de Proteína , Aminoácidos/genética , Animales , Sitios de Unión , Genes Duplicados/genética , Variación Genética , Ligandos , Peso Molecular , Filogenia , Selección Genética , Homología de Secuencia de Aminoácido , Especificidad de la Especie , Electricidad Estática
8.
PLoS One ; 6(11): e26641, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22069460

RESUMEN

Recent advancements in genomics provide new tools for evolutionary ecological research. The paper wasp genus Polistes is a model for social insect evolution and behavioral ecology. We developed RNA interference (RNAi)-mediated gene silencing to explore proposed connections between expression of hexameric storage proteins and worker vs. gyne (potential future foundress) castes in naturally-founded colonies of P. metricus. We extended four fragments of putative hexamerin-encoding P. metricus transcripts acquired from a previous study and fully sequenced a gene that encodes Hexamerin 2, one of two proposed hexameric storage proteins of P. metricus. MALDI-TOF/TOF, LC-MSMS, deglycosylation, and detection of phosphorylation assays showed that the two putative hexamerins diverge in peptide sequence and biochemistry. We targeted the hexamerin 2 gene in 5(th) (last)-instar larvae by feeding RNAi-inducing double-stranded hexamerin 2 RNA directly to larvae in naturally-founded colonies in the field. Larval development and adult traits were not significantly altered in hexamerin 2 knockdowns, but there were suggestive trends toward increased developmental time and less developed ovaries, which are gyne characteristics. By demonstrating how data acquisition from 454/Roche pyrosequencing can be combined with biochemical and proteomics assays and how RNAi can be deployed successfully in field experiments on Polistes, our results pave the way for functional genomic research that can contribute significantly to learning the interactions of environment, development, and the roles they play in paper wasp evolution and behavioral ecology.


Asunto(s)
Evolución Biológica , Proteínas de Insectos , Interferencia de ARN , Predominio Social , Avispas , Animales , Secuencia de Aminoácidos , Secuencia de Bases , Ecología , Glicosilación , Hemolinfa , Proteínas de Insectos/antagonistas & inhibidores , Proteínas de Insectos/genética , Larva/genética , Larva/crecimiento & desarrollo , Datos de Secuencia Molecular , Fenotipo , Fosforilación , ARN Bicatenario/genética , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Avispas/genética
9.
Protein Sci ; 17(9): 1513-21, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18552126

RESUMEN

Streptococcus suis Dpr is an iron-binding protein involved in oxidative stress resistance. It belongs to the bacterial Dps protein family whose members form dodecameric assemblies. Previous studies have shown that zinc and terbium inhibit iron incorporation in Listeria innocua Dps protein. In order to gain structural insights into the inhibitory effect of zinc and terbium, the crystal structures of Streptococcus suis Dpr complexes with these ions were determined at 1.8 A and 2.1 A, respectively. Both ions were found to bind at the ferroxidase center and in the same location as iron. In addition, a novel zinc-binding site formed by His40 and His44 was identified. Both His residues were found to be present within all known Streptococcus suis Dpr variants and in Streptococcus pneumoniae, Streptococcus gordonii, and Streptococcus sanguinis Dpr proteins. Amino acid sequence alignment of Dpr with other Dps family members revealed that His44 is highly conserved, in contrast to His40. The inhibitory effect of zinc and terbium on iron oxidation in Dpr was studied in vitro, and it was found that both ions at concentrations >0.2 mM almost completely abolish iron binding. These results provide a structural basis for the inhibitory effect of zinc and terbium in the Dps family of proteins, and suggest a potential role of the Dps proteins in zinc detoxification mechanisms involving the second zinc-binding site.


Asunto(s)
Proteínas Bacterianas/química , Ceruloplasmina/antagonistas & inhibidores , Proteínas de Unión al ADN/química , Streptococcus suis/química , Terbio/química , Zinc/química , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Sitios de Unión , Cristalografía por Rayos X , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Ferritinas/metabolismo , Genes Bacterianos , Histidina/química , Humanos , Modelos Moleculares , Datos de Secuencia Molecular , Unión Proteica , Homología de Secuencia de Aminoácido , Streptococcus suis/genética , Streptococcus suis/aislamiento & purificación , Streptococcus suis/metabolismo , Terbio/metabolismo , Agua/química , Zinc/metabolismo
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