A structural view of egg coat architecture and function in fertilization.

Species-restricted interaction between gametes at the beginning of fertilization is mediated by the extracellular coat of the egg, a matrix of cross-linked glycoprotein filaments called the zona pellucida (ZP) in mammals and the vitelline envelope in nonmammals. All egg coat subunits contain a conserved protein-protein interaction module-the "ZP domain"-that allows them to polymerize upon dissociation of a C-terminal propeptide containing an external hydrophobic patch (EHP). Recently, the first crystal structures of a ZP domain protein, sperm receptor ZP subunit zona pellucida glycoprotein 3 (ZP3), have been reported, giving a glimpse of the structural organization of the ZP at the atomic level and the molecular basis of gamete recognition in vertebrates. The ZP module is divided in two related immunoglobulin-like domains, ZP-N and ZP-C, that contain characteristic disulfide bond patterns and, in the case of ZP-C, also incorporate the EHP. This segment lies at the interface between the two domains, which are connected by a long loop carrying a conserved O-glycan important for binding to sperm in vitro. The structures explain several apparently contradictory observations by reconciling the variable disulfide bond patterns found in different homologues of ZP3 as well as the multiple ZP3 determinants alternatively involved in gamete interaction. These findings have implications for our understanding of ZP subunit biogenesis; egg coat assembly, architecture, and interaction with sperm; structural rearrangements leading to postfertilization hardening of the ZP and the block to sperm binding; and the evolutionary origin of egg coats

Tracking Down the ZP Domain: From the Mammalian Zona Pellucida to the Molluscan Vitelline Envelope

Oocytes from virtually all organisms are surrounded by at least one coat. This specialized extracellular matrix, called the zona pellucida (ZP) in mammals and the vitelline envelope (VE) in nonmammals, has a structural function and plays essential roles in oogenesis, fertilization, and early development. During the last 15 years, compelling evidence has accumulated that all ZP/VE subunits polymerize using a conserved sequence, the ZP domain, so that the basic structural features of egg coat matrices have been maintained through evolution. Moreover, ZP domains have been identified in many other polymeric extracellular proteins from eukaryotes. This review compares the ultrastructure and molecular composition of egg coats from mollusc to human, suggests a common mechanism for assembly of ZP/VE proteins, and discusses alternative models of how these could be arranged within filaments

Mitochondrial transport and metabolism of the vitamin B-derived cofactors thiamine pyrophosphate, coenzyme A, FAD and NAD+, and related diseases: A review

Multiple mitochondrial matrix enzymes playing key roles in metabolism require cofactors for their action. Due to the high impermeability of the mitochondrial inner membrane, these cofactors need to be synthesized within the mitochondria or be imported, themselves or one of their precursors, into the organelles. Transporters belonging to the protein family of mitochondrial carriers have been identified to transport the coenzymes: thiamine pyrophosphate, coenzyme A, FAD and NAD+, which are all structurally similar to nucleotides and derived from different B-vitamins. These mitochondrial cofactors bind more or less tightly to their enzymes and, after having been involved in a specific reaction step, are regenerated, spontaneously or by other enzymes, to return to their active form, ready for the next catalysis round. Disease-causing mutations in the mitochondrial cofactor carrier genes compromise not only the transport reaction but also the activity of all mitochondrial enzymes using that particular cofactor and the metabolic pathways in which the cofactor-dependent enzymes are involved. The mitochondrial transport, metabolism and diseases of the cofactors thiamine pyrophosphate, coenzyme A, FAD and NAD+ are the focus of this review

Los valles tectónicos recientes de Rubielos de la Cerida (Teruel)

[Resumen] La actividad tectónica cuaternaria y reciente ha dado lugar en este área a un conjunto de depresiones alargadas de orientación submeridiana, enmarcadas por fallas, que constituyen valles tectónicos[Abstract] Quaternary and recent tectonic activity led to a series of elongated depressions in the studied area of roughly N-S orientation, framed by faults, and developping as tectonic valleys

Crystal structure of the ZP-N domain of ZP3 reveals the core fold of animal egg coats

Species-specific recognition between the egg extracellular matrix (zona pellucida) and sperm is the first, crucial step of mammalian fertilization. Zona pellucida filament components ZP3 and ZP2 act as sperm receptors, and mice lacking either of the corresponding genes produce oocytes without a zona pellucida and are completely infertile. Like their counterparts in the vitelline envelope of non-mammalian eggs and many other secreted eukaryotic proteins, zona pellucida subunits polymerize using a 'zona pellucida (ZP) domain' module, whose conserved amino-terminal part (ZP-N) was suggested to constitute a domain of its own. No atomic structure has been reported for ZP domain proteins, and there is no structural information on any conserved vertebrate protein that is essential for fertilization and directly involved in egg-sperm binding. Here we describe the 2.3 ångström (A) resolution structure of the ZP-N fragment of mouse primary sperm receptor ZP3. The ZP-N fold defines a new immunoglobulin superfamily subtype with a beta-sheet extension characterized by an E' strand and an invariant tyrosine residue implicated in polymerization. The structure strongly supports the presence of ZP-N repeats within the N-terminal region of ZP2 and other vertebrate zona pellucida/vitelline envelope proteins, with implications for overall egg coat architecture, the post-fertilization block to polyspermy and speciation. Moreover, it provides an important framework for understanding human diseases caused by mutations in ZP domain proteins and developing new methods of non-hormonal contraception

Morfología de vertientes y neotectónica en el Macizo de Javalambre (provincia de Teruel)

[Resumen] El modelado actual de las vertientes del macizo de Javalambre es consecuencia de tres tipos principales de procesos que actúan a partir de su elevación a comienzos del Plioceno -superior: (a) la dinámica periglaciar, (b) una etapa de activida~ tect6nica ocurrida hacia el Pleistoceno medio-superior, y (c) deslizamientos gravitacionales, translacionales y rotacionales producidos a favor de un sustrato plástico en las áreas de mayor incisión de la red -fluvial.Abstract] The present slope form in Javalambre area results from three principal types of processes which are active after its elevation in the early Upper Pliocene: (a) periglacial dynamics, (b) a tectonic phase in Middle-Upper Pleistocene, and (c) gravitational, translational and rotational landslides generated over plastic rocks in zones with a intensive fluvial incisio

Evidence for Non-Essential Salt Bridges in the M-Gates of Mitochondrial Carrier Proteins

Mitochondrial carriers, which transport metabolites, nucleotides, and cofactors across the mitochondrial inner membrane, have six transmembrane α-helices enclosing a translocation pore with a central substrate binding site whose access is controlled by a cytoplasmic and a matrix gate (M-gate). The salt bridges formed by the three PX[DE]XX[RK] motifs located on the odd-numbered transmembrane α-helices greatly contribute to closing the M-gate. We have measured the transport rates of cysteine mutants of the charged residue positions in the PX[DE]XX[RK] motifs of the bovine oxoglutarate carrier, the yeast GTP/GDP carrier, and the yeast NAD+ transporter, which all lack one of these charged residues. Most single substitutions, including those of the non-charged and unpaired charged residues, completely inactivated transport. Double mutations of charged pairs showed that all three carriers contain salt bridges non-essential for activity. Two double substitutions of these non-essential charge pairs exhibited higher transport rates than their corre-sponding single mutants, whereas swapping the charged residues in these positions did not increase activity. The results demonstrate that some of the residues in the charged residue positions of the PX[DE]XX[KR] motifs are important for reasons other than forming salt bridges, probably for playing specific roles related to the substrate interaction-mediated conformational changes leading to the M-gate opening/closing

Phytochemicals of minthostachys diffusa epling and their health-promoting bioactivities

The genus Minthostachys belonging to the Lamiaceae family, and is an important South American mint genus used commonly in folk medicine as an aroma in cooking. The phytochemical-rich samples of the aerial parts of Minthostachys diffusa Epling. were tested for pharmacological and health-promoting bioactivities using in vitro chemical and enzymatic assays. A range of radical scavenging activities of the samples against biological radicals such as nitric oxide and superoxide anion and against synthetic 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, the ferric reducing antioxidant power and the lipid peroxidation inhibition were determined and ranked using the 'relative antioxidant capacity index' (RACI). The ethyl acetate fraction showed the highest RACI of +1.12. Analysis of the various fractions' inhibitory ability against enzymes involved in diabetes (α-amylase and α-glucosidase), and against enzymes associated with Parkinson's or Alzheimer's diseases (acetylcholinesterase and butyrylcholinesterase) also suggested that the ethyl acetate fraction was the most active. Liquid chromatography-tandem mass spectrometry analysis of the ethyl acetate fraction showed more than 30 polyphenolic compounds, including triterpenes. The inhibitory cholinesterase effects of the triterpenes identified from M. diffusa were further analysed by in silico docking of these compounds into 3D-structures of acetylcholinesterase and butyrylcholinesterase. This is the first study on pharmacological activities and phytochemical profiling of the aerial parts of M. diffusa, showing that this plant, normally used as food in South America, is also rich in health-promoting phytochemicals

A new monoclonal antibody detects downregulation of protein tyrosine phosphatase receptor type γ in chronic myeloid leukemia patients

Background: Protein tyrosine phosphatase receptor gamma (PTPRG) is a ubiquitously expressed member of the protein tyrosine phosphatase family known to act as a tumor suppressor gene in many different neoplasms with mechanisms of inactivation including mutations and methylation of CpG islands in the promoter region. Although a critical role in human hematopoiesis and an oncosuppressor role in chronic myeloid leukemia (CML) have been reported, only one polyclonal antibody (named chPTPRG) has been described as capable of recognizing the native antigen of this phosphatase by flow cytometry. Protein biomarkers of CML have not yet found applications in the clinic, and in this study, we have analyzed a group of newly diagnosed CML patients before and after treatment. The aim of this work was to characterize and exploit a newly developed murine monoclonal antibody specific for the PTPRG extracellular domain (named TPγ B9-2) to better define PTPRG protein downregulation in CML patients. Methods: TPγ B9-2 specifically recognizes PTPRG (both human and murine) by flow cytometry, western blotting, immunoprecipitation, and immunohistochemistry. Results: Co-localization experiments performed with both anti-PTPRG antibodies identified the presence of isoforms and confirmed protein downregulation at diagnosis in the Philadelphia-positive myeloid lineage (including CD34+/CD38bright/dim cells). After effective tyrosine kinase inhibitor (TKI) treatment, its expression recovered in tandem with the return of Philadelphia-negative hematopoiesis. Of note, PTPRG mRNA levels remain unchanged in tyrosine kinase inhibitors (TKI) non-responder patients, confirming that downregulation selectively occurs in primary CML cells. Conclusions: The availability of this unique antibody permits its evaluation for clinical application including the support for diagnosis and follow-up of these disorders. Evaluation of PTPRG as a potential therapeutic target is also facilitated by the availability of a specific reagent capable to specifically detect its target in various experimental conditions

Paleotsunami evidence in the Bahía Inglesa coast (Atacama, Chile) based on a multi-approach analysis

The Atacama coast is located in an area with a current high risk of tsunami, and the sedimentary deposits found in the Bahía Inglesa area, in the Morro sector, clearly indicate that this was also the case in the past. This investigation analyzes a paleotsunami sedimentary deposit consisting of a block field associated with three sand lobes oriented towards land on top of a marine terrace at an altitude of 70–75 m, which originated from a tsunamigenic event occurred between interglacial periods MIS 7 (ca. 210 ± 10 ky) and MIS5e (ca. 125 ± 5 ky). The deposits have been studied using a multiple approach combining geomorphological, sedimentological, biological, and geochemical criteria. The first type of criteria clearly indicate that the energy required to move the blocks and form the sand lobes could only have been generated by a tsunami. Sedimentological criteria constitute direct evidences of a marine origin due to the presence of siliceous remains from diatom species and spicules from strictly marine sponges, while geochemical criteria, such as the stable isotope signature and chemical composition, constitute evidence of a marine intrusion. © 2022, The Author(s)