Abstract Background The LYP tyrosine phosphatase presents a SNP (1858C > T) that increases the risk of developing autoimmune diseases such as type I diabetes and arthritis. It remains unclear how this SNP affects LYP function and promotes the development of these diseases. The scarce information about LYP substrates is in part responsible for the poor understanding of LYP function. Results In this study, we identify in T lymphocytes several adaptor proteins as potential substrates targeted by LYP, including FYB, SLP-76, HS-1, Vav, SKAP1 and SKAP2. We also show that LYP co-localizes with SLP76 in microclusters, upon TCR engagement. Conclusions These data indicate that LYP may modulate T cell activation by dephosphorylating several adaptor proteins, such as FYB, SLP-76, HS-1, Vav, SKAP1 and SKAP2 upon TCR engagement.

SARS-CoV-2 infection can cause severe pneumonia, wherein exacerbated inflammation plays a major role. This is reminiscent of the process commonly termed cytokine storm, a condition dependent on a disproportionated production of cytokines. This state involves the activation of the innate immune response by viral patterns and coincides with the biosynthesis of the biomass required for viral replication, which may overwhelm the capacity of the endoplasmic reticulum and drive the unfolded protein response (UPR). The UPR is a signal transduction pathway composed of three branches that is initiated by a set of sensors: inositol-requiring protein 1 (IRE1), protein kinase RNA-like ER kinase (PERK), and activating transcription factor 6 (ATF6). These sensors control adaptive processes, including the transcriptional regulation of proinflammatory cytokines. Based on this background, the role of the UPR in SARS-CoV-2 replication and the ensuing inflammatory response was investigated using in vivo and in vitro models of infection. Mice and Syrian hamsters infected with SARS-CoV-2 showed a sole activation of the Ire1α-Xbp1 arm of the UPR associated with a robust production of proinflammatory cytokines. Human lung epithelial cells showed the dependence of viral replication on the expression of UPR-target proteins branching on the IRE1α-XBP1 arm and to a lower extent on the PERK route. Likewise, activation of the IRE1α-XBP1 branch by Spike (S) proteins from different variants of concern was a uniform finding. These results show that the IRE1α-XBP1 system enhances viral replication and cytokine expression and may represent a potential therapeutic target in SARS-CoV-2 severe pneumonia.

Dadas las dificultades identificadas por parte de los profesores del perfil de Genética del Dpto. de Producción Animal de la Universidad de León, integrantes a su vez del Grupo de Innovación Docente "VetGeneULE" (GI052), en relación al aprendizaje de los conceptos de Genética Cuantitativa en diferentes asignaturas relacionadas con la Mejora Genética Animal, se ha diseñado un juego de cartas didácticas para reforzar la comprensión de dichos conceptos. En base a un estudio piloto realizado previamente en un número reducido de estudiantes del Grado de Ingeniería Agrícola, se presenta aquí el proceso de desarrollo de la versión definitiva del juego de cartas, denominado "Familias Falconer" y la evaluación de una primera experiencia de gamificación desarrollada con un grupo de estudiantes de mayor tamaño de la asignatura de Cría y Mejora Animal del Grado en Veterinaria de la Universidad de León. Bayón, Yolanda; Suárez-Vega, Aroa; Fonseca, Pablo A.S.; Pelayo, Rocío; de la Fuente, Fernando; Arranz, Juan-José; Gutiérrez-Gil, Beatriz

Mutations in the adaptor protein PSTPIP1 cause a spectrum of autoinflammatory diseases, including PAPA and PAMI; however, the mechanism underlying these diseases remains unknown. Most of these mutations lie in PSTPIP1 F-BAR domain, which binds to LYP, a protein tyrosine phosphatase associated with arthritis and lupus. To shed light on the mechanism by which these mutations generate autoinflammatory disorders, we solved the structure of the F-BAR domain of PSTPIP1 alone and bound to the C-terminal homology segment of LYP, revealing a novel mechanism of recognition of Pro-rich motifs by proteins in which a single LYP molecule binds to the PSTPIP1 F-BAR dimer. The residues R228, D246, E250, and E257 of PSTPIP1 that are mutated in immunological diseases directly interact with LYP. These findings link the disruption of the PSTPIP1/LYP interaction to these diseases, and support a critical role for LYP phosphatase in their pathogenesis.

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A. Suárez-Vega , J.J. Arranz , Y. Bayón , L.F. de la Fuente , B. Gutiérrez-Gil Universidad de León (SPAIN)

Diffraction images of a crystal of the F-BAR domain of human PSTPIP1 (residues 1-289, Uniprot reference O43586-1) in complex with the CTH of LYP (residues 787-807, Uniprot Q9Y2R2-1). Data were collected on a single crystal at the beamline i03 of the Diamond Light Source synchrotron (Didcot, UK) using radiation of 0.99987 Å wavelength and a PILATUS3 6M detector. The dataset consists of 3 groups, each containing of 1800 images (0.1 degree oscillation per image), collected at three different positions of the same crystal. Crystal belongs to the space group P2(1)2(1)2(1) with unit cell dimensions a=48.0 Å, b=72.0 Å, c=205.0 Å. The asymmetric unit contains an homodimer of the F-BAR domain bound to a LYP-CTH (~53% solvent content), which is the biological complex. Diffraction data was notably anisotropic. The lowest resolution limit was 4.05 Å in the direction b* and the highest limits were 2.11 Å and 2.10 in the directions a* and c*, respectively. The structure derived form these data is published in: Manso, J.A., Marcos, T., Ruiz-Martín, V. Casas J, Alcón P, Sánchez Crespo M, Bayón Y, de Pereda JM, Alonso A PSTPIP1-LYP phosphatase interaction: structural basis and implications for autoinflammatory disorders. Cell. Mol. Life Sci. 79, 131 (2022). https://doi.org/10.1007/s00018-022-04173-w The structure is available at the PDB under the code 7AAM: https://www.ebi.ac.uk/pdbe/entry/pdb/7aam

In higher eukaryotes, the Tyr phosphorylation status of cellular proteins results from the coordinated action of Protein Tyrosine Kinases (PTKs) and Protein Tyrosine Phosphatases (PTPs). PTPs have emerged as highly regulated enzymes with diverse substrate specificity, and proteins with Tyr-dephosphorylation or Tyr-dephosphorylation-like properties can be clustered as the PTPome. This includes proteins from the PTP superfamily, which display a Cys-based catalytic mechanism, as well as enzymes from other gene families (Asp-based phosphatases, His-based phosphatases) that have converged in protein Tyr-dephosphorylation-related functions by using non-Cys-based catalytic mechanisms. Within the Cys-based members of the PTPome, classical PTPs dephosphorylate specific phosphoTyr (pTyr) residues from protein substrates, whereas VH1-like dual-specificity PTPs dephosphorylate pTyr, pSer, and pThr residues, as well as nonproteinaceous substrates, including phosphoinositides and phosphorylated carbohydrates. In addition, several PTPs have impaired catalytic activity as a result of amino acid substitutions at their active sites, but retain regulatory functions related with pTyr signaling. As a result of their relevant biological activity, many PTPs are linked to human disease, including cancer, neurodevelopmental, and metabolic diseases, making these proteins important drug targets and molecular markers in the clinic. Here, a brief overview on the biochemistry and physiology of the different groups of proteins that belong to the mammalian PTPome is presented.

Proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1) is an adaptor protein associated with the cytoskeleton that is mainly expressed in hematopoietic cells. Mutations in PSTPIP1 cause the rare autoinflammatory disease called pyogenic arthritis, pyoderma gangrenosum, and acne. We carried out this study to further our knowledge on PSTPIP1 function in T cells, particularly in relation to the phosphatase lymphoid phosphatase (LYP), which is involved in several autoimmune diseases. LYP-PSTPIP1 binding occurs through the C-terminal homology domain of LYP and the F-BAR domain of PSTPIP1. PSTPIP1 inhibits T-cell activation upon T-cell receptor (TCR) and CD28 engagement, regardless of CD2 costimulation. This function of PSTPIP1 depends on the presence of an intact SH3 domain rather than on the F-BAR domain, indicating that ligands of the F-BAR domain, such as the PEST phosphatases LYP and PTP-PEST, are not critical for its negative regulatory role in TCR signaling. Additionally, PSTPIP1 mutations that cause the pyogenic arthritis, pyoderma gangrenosum and acne syndrome do not affect PSTPIP1 function in T-cell activation through the TCR.

The protein tyrosine phosphatase LYP, a key regulator of TCR signaling, presents a single nucleotide polymorphism, C1858T, associated with several autoimmune diseases such as type I diabetes, rheumatoid arthritis, and lupus. This polymorphism changes an R by a W in the P1 Pro rich motif of LYP, which binds to CSK SH3 domain, another negative regulator of TCR signaling. Based on the analysis of the mouse homologue, Pep, it was proposed that LYP and CSK bind constitutively to inhibit LCK and subsequently TCR signaling. The detailed study of LYP/CSK interaction, here presented, showed that LYP/CSK interaction was inducible upon TCR stimulation, and involved LYP P1 and P2 motifs, and CSK SH3 and SH2 domains. Abrogating LYP/CSK interaction did not preclude the regulation of TCR signaling by these proteins.

In this study, we used the Illumina OvineSNP50 BeadChip to conduct a genome-wide association (GWA) analysis for milk production traits in dairy sheep by analyzing a commercial population of Spanish Churra sheep. The studied population consisted of a total of 1,681 Churra ewes belonging to 16 half-sib families with available records for milk yield (MY), milk protein and fat yields (PY and FY) and milk protein and fat contents (PP and FP). The most significant association identified reached experiment-wise significance for PP and FP and was located on chromosome 3 (OAR3). These results confirm the population-level segregation of a previously reported QTL affecting PP and suggest that this QTL has a significant pleiotropic effect on FP. Further associations were detected at the chromosome-wise significance level on 14 other chromosomal regions. The marker on OAR3 showing the highest significant association was located at the third intron of the alpha-lactalbumin (LALBA) gene, which is a functional and positional candidate underlying this association. Sequencing this gene in the 16 Churra rams of the studied resource population identified additional polymorphisms. One out of the 31 polymorphisms identified was located within the coding gene sequence (LALBA_g.242T>C) and was predicted to cause an amino acid change in the protein (Val27Ala). Different approaches, including GWA analysis, a combined linkage and linkage disequilibrium study and a concordance test with the QTL segregating status of the sires, were utilized to assess the role of this mutation as a putative QTN for the genetic effects detected on OAR3. Our results strongly support the polymorphism LALBA_g.242T>C as the most likely causal mutation of the studied OAR3 QTL affecting PP and FP, although we cannot rule out the possibility that this SNP is in perfect linkage disequilibrium with the true causal polymorphism.

BACKGROUND:For ruminants reared on grazing systems, gastrointestinal nematode (GIN) parasite infections represent the class of diseases with the greatest impact on animal health and productivity. Among the many possible strategies for controlling GIN infection, the enhancement of host resistance through the selection of resistant animals has been suggested by many authors. Because of the difficulty of routinely collecting phenotypic indicators of parasite resistance, information derived from molecular markers may be used to improve the efficiency of classical genetic breeding.METHODS:A total of 181 microsatellite markers evenly distributed along the 26 sheep autosomes were used in a genome scan analysis performed in a commercial population of Spanish Churra sheep to detect chromosomal regions associated with parasite resistance. Following a daughter design, we analysed 322 ewes distributed in eight half-sib families. The phenotypes studied included two faecal egg counts (LFEC0 and LFEC1), anti-Teladorsagia circumcincta LIV IgA levels (IgA) and serum pepsinogen levels (Peps).RESULTS:The regression analysis revealed one QTL at the 5% genome-wise significance level on chromosome 6 for LFEC1 within the marker interval BM4621-CSN3. This QTL was found to be segregating in three out of the eight families analysed. Four other QTL were identified at the 5% chromosome-wise level on chromosomes 1, 10 and 14. Three of these QTL influenced faecal egg count, and the other one had an effect on IgA levels.CONCLUSION:This study has successfully identified segregating QTL for parasite resistance traits in a commercial population. For some of the QTL detected, we have identified interesting coincidences with QTL previously reported in sheep, although most of those studies have been focused on young animals. Some of these coincidences might indicate that some common underlying loci affect parasite resistance traits in different sheep breeds. The identification of new QTL may suggest the existence of complex host-parasite relationships that have unique features depending on the host-parasite combination, perhaps due to the different mechanisms underlying resistance in adult sheep (hypersensitivity reactions) and lambs (immunity). The most significant QTL identified on chromosome 6 for LFEC(1) may be the target for future fine-mapping research efforts.

YopH is an exceptionally active tyrosine phosphatase that is essential for virulence of Yersinia pestis, the bacterium causing plague. YopH breaks down signal transduction mechanisms in immune cells and inhibits the immune response. Only a few substrates for YopH have been characterized so far, for instance p130Cas and Fyb, but in view of YopH potency and the great number of proteins involved in signalling pathways it is quite likely that more proteins are substrates of this phosphatase. In this respect, we show here YopH interaction with several proteins not shown before, such as Gab1, Gab2, p85, and Vav and analyse the domains of YopH involved in these interactions. Furthermore, we show that Gab1, Gab2 and Vav are not dephosphorylated by YopH, in contrast to Fyb, Lck, or p85, which are readily dephosphorylated by the phosphatase. These data suggests that YopH might exert its actions by interacting with adaptors involved in signal transduction pathways, what allows the phosphatase to reach and dephosphorylate its susbstrates.

Potassium channel tetramerization domain (KCTD) proteins contain a bric-a-brac, tramtrak and broad complex (BTB) domain that is most similar to the tetramerization domain (T1) of voltage-gated potassium channels. Some BTB-domain-containing proteins have been shown recently to participate as substrate-specific adaptors in multimeric cullin E3 ligase reactions by recruiting proteins for ubiquitination and subsequent degradation by the proteasome. Twenty-two KCTD proteins have been found in the human genome, but their functions are largely unknown. In this study, we have characterized KCTD5, a new KCTD protein found in the cytosol of cultured cell lines. The expression of KCTD5 was upregulated post-transcriptionally in peripheral blood lymphocytes stimulated through the T-cell receptor. KCTD5 interacted specifically with cullin3, bound ubiquitinated proteins, and formed oligomers through its BTB domain. Analysis of the interaction with cullin3 showed that, in addition to the BTB domain, some amino acids in the N-terminus of KCTD5 are required for binding to cullin3. These findings suggest that KCTD5 is a substrate-specific adaptor for cullin3-based E3 ligases.

Se estudio la variabilidad en el DNA mitocondrial en distintas razas ovinas ibericas y los resultados obtenidos se analizaron para cada uno los cuatro troncos etnologicos. Se identificaron los tres linajes maternos conocidos como B, A y C. La diversidad nucleotidica promedio estimada para cada uno de los grupos ovinos fue menor para el tronco churro, intermedia para los grupos entrefino y merino, mientras que el tronco iberico mostro la mayor diversidad mitocondrial. En el tronco churro todas las secuencias de DNA mitocondrial correspondieron al haplogrupo B, tambien denominado europeo, y entre sus razas la Latxa fue la de menor diversidad de todos las razas Ibericas analizadas. En el tronco entrefino se identificaron unos pocos animales del linaje materno A, o asiatico, en concreto en la raza espanola Manchega y en la portuguesa Serra da Estrela. En la agrupacion merina se encontraron diferencias entre la raza Merino Branco y el resto, mostrando la primera una diversidad nucleotidica muy superior, asi como la presencia de algunos animales del linaje A. Por el contrario, en el resto de las poblaciones merinas, entre ellas el Merino puro espanol, se detecto una variabilidad moderada y sus animales pertenecian en todos los casos al linaje materno B. Finalmente, el tronco iberico presento el valor promedio mas elevado de diversidad nucleotidica y en esta agrupacion ovina se identifico el linaje materno C. La presencia de este tipo de DNA mitocondrial fue puesta de manifiesto en ambas razas representantes de este tronco, Montesina y Ojalada. Este resultado es de particular relevancia dado que este linaje materno ha sido descubierto no hace mucho tiempo y fundamentalmente en ovinos asiaticos.