Human uterine natural killer cells regulate differentiation of extravillous trophoblast early in pregnancy

In humans, balanced invasion of trophoblast cells into the uterine mucosa, the decidua, is critical for successful pregnancy. Evidence suggests that this process is regulated by uterine natural killer (uNK) cells, but how they influence reproductive outcomes is unclear. Here, we used our trophoblast organoids and primary tissue samples to determine how uNK cells affect placentation. By locating potential interaction axes between trophoblast and uNK cells using single-cell transcriptomics and in vitro modeling of these interactions in organoids, we identify a uNK cell-derived cytokine signal that promotes trophoblast differentiation at the late stage of the invasive pathway. Moreover, it affects transcriptional programs involved in regulating blood flow, nutrients, and inflammatory and adaptive immune responses, as well as gene signatures associated with disorders of pregnancy such as pre-eclampsia. Our findings suggest mechanisms on how optimal immunological interactions between uNK cells and trophoblast enhance reproductive success.

Myosin VI regulates ciliogenesis by promoting the turnover of the centrosomal/satellite protein OFD1

The actin motor protein myosin VI is a multivalent protein with diverse functions. Here, we identified and characterised a myosin VI ubiquitous interactor, the oral‐facial‐digital syndrome 1 (OFD1) protein, whose mutations cause malformations of the face, oral cavity, digits and polycystic kidney disease. We found that myosin VI regulates the localisation of OFD1 at the centrioles and, as a consequence, the recruitment of the distal appendage protein Cep164. Myosin VI depletion in non‐tumoural cell lines causes an aberrant localisation of OFD1 along the centriolar walls, which is due to a reduction in the OFD1 mobile fraction. Finally, loss of myosin VI triggers a severe defect in ciliogenesis that could be, at least partially, ascribed to an impairment in the autophagic removal of OFD1 from satellites. Altogether, our results highlight an unprecedent layer of regulation of OFD1 and a pivotal role of myosin VI in coordinating the formation of the distal appendages and primary cilium with important implications for the genetic disorders known as ciliopathies.

ENABLE 2017, the First European PhD and Post-Doc Symposium. Session 2: The OMICS Revolution

The European Academy for Biomedical Science (ENABLE) is an initiative funded by the European Union Horizon 2020 program involving four renowned European Research Institutes (Institute for Research in Biomedicine—IRB Barcelona, Spain; Radboud Institute for Molecular Life Sciences—RIMLS, The Netherlands; Novo Nordisk Foundation Center for Protein Research—NNF CPR, Denmark; European School of Molecular Medicine—SEMM, Italy) and an innovative science communication agency (Scienseed). With the aim of promoting biomedical science of excellence in Europe, ENABLE organizes an annual three-day international event. This gathering includes a top-level scientific symposium bringing together leading scientists, PhD students, and post-doctoral fellows; career development activities supporting the progression of young researchers and fostering discussion about opportunities beyond the bench; and outreach activities stimulating the interaction between science and society. The first European PhD and Post-Doc Symposium, entitled “Breaking Down Complexity: Innovative Models and Techniques in Biomedicine”, was hosted by the vibrant city of Barcelona. The scientific program of the conference was focused on the most recent advances and applications of modern techniques and models in biomedical research and covered a wide range of topics, from synthetic biology to translational medicine. Overall, the event was a great success, with more than 200 attendees from all over Europe actively participating in the symposium by presenting their research and exchanging ideas with their peers and world-renowned scientists.

ENABLE 2017, the First European PhD and Post-Doc Symposium. Session 1: Building the Foundations of Biology: Synthetic and Cellular Research

The European Academy for Biomedical Science (ENABLE) is an initiative funded by the European Union Horizon 2020 program involving four renowned European Research Institutes (Institute for Research in Biomedicine—IRB Barcelona, Spain; Radboud Institute for Molecular Life Sciences—RIMLS, the Netherlands; Novo Nordisk Foundation Center for Protein Research—NNF CPR, Denmark; European School of Molecular Medicine—SEMM, Italy) and an innovative science communication agency (Scienseed). With the aim of promoting biomedical science of excellence in Europe, ENABLE organizes an annual three-day international event. This gathering includes a top-level scientific symposium bringing together leading scientists, PhD students, and post-doctoral fellows; career development activities supporting the progression of young researchers and fostering discussion about opportunities beyond the bench; and outreach activities stimulating the interaction between science and society. The first European PhD and Postdoc Symposium, entitled “Breaking Down Complexity: Innovative Models and Techniques in Biomedicine”, was hosted by the vibrant city of Barcelona. The scientific program of the conference was focused on the most recent advances and applications of modern techniques and models in biomedical research and covered a wide range of topics, from synthetic biology to translational medicine. Overall, the event was a great success, with more than 200 attendees from all over Europe actively participating in the symposium by presenting their research and exchanging ideas with their peers and world-renowned scientists.

Desmoplakin maintains gap junctions by inhibiting Ras/MAPK and lysosomal degradation of connexin-43

Desmosomal mutations result in potentially deadly cardiocutaneous disease caused by electrical conduction defects and disruption of gap junctions. Kam et al. demonstrate a mechanism whereby loss of the intermediate filament anchoring protein desmoplakin stimulates Cx43 turnover by increasing K-Ras expression, marking Cx43 for lysosomal degradation through ERK1/2 phosphorylation.

Desmoplakin (DP) is an obligate component of desmosomes, intercellular adhesive junctions that maintain the integrity of the epidermis and myocardium. Mutations in DP can cause cardiac and cutaneous disease, including arrhythmogenic cardiomyopathy (ACM), an inherited disorder that frequently results in deadly arrhythmias. Conduction defects in ACM are linked to the remodeling and functional interference with Cx43-based gap junctions that electrically and chemically couple cells. How DP loss impairs gap junctions is poorly understood. We show that DP prevents lysosomal-mediated degradation of Cx43. DP loss triggered robust activation of ERK1/2–MAPK and increased phosphorylation of S279/282 of Cx43, which signals clathrin-mediated internalization and subsequent lysosomal degradation of Cx43. RNA sequencing revealed Ras-GTPases as candidates for the aberrant activation of ERK1/2 upon loss of DP. Using a novel Ras inhibitor, Ras/Rap1-specific peptidase (RRSP), or K-Ras knockdown, we demonstrate restoration of Cx43 in DP-deficient cardiomyocytes. Collectively, our results reveal a novel mechanism for the regulation of the Cx43 life cycle by DP in cardiocutaneous models.

ENABLE 2017, the First EUROPEAN PhD and Post-Doc Symposium. Session 3: In Vitro to In Vivo: Modeling Life in 3D

The EUROPEAN ACADEMY FOR BIOMEDICAL SCIENCE (ENABLE) is an initiative funded by the European Union Horizon 2020 program involving four renowned European research institutes (Institute for Research in Biomedicine-IRB Barcelona, Spain; Radboud Institute for Molecular Life Sciences-RIMLS, the Netherlands; Novo Nordisk Foundation Center for Protein Research-NNF CPR, Denmark; European School of Molecular Medicine-SEMM, Italy) and an innovative science communication agency (Scienseed). With the aim to promote biomedical science of excellence in Europe, ENABLE organizes an annual three-day international event. This gathering includes a top-level scientific symposium bringing together leading scientists, PhD students, and post-doctoral fellows; career development activities supporting the progression of young researchers and fostering discussion about opportunities beyond the bench; outreach activities stimulating the interaction between science and society. The first European PhD and Postdoc Symposium, entitled "Breaking Down Complexity: Innovative models and techniques in biomedicine", was hosted by the vibrant city of Barcelona. The scientific program of the conference was focused on the most recent advances and applications of modern techniques and models in biomedical research and covered a wide range of topics, from synthetic biology to translational medicine. Overall, the event was a great success, with more than 200 attendees from all over Europe actively participating in the symposium by presenting their research and exchanging ideas with their peers and world-renowned scientists.

Myosin VI Contains a Compact Structural Motif that Binds to Ubiquitin Chains

Myosin VI is critical for cargo trafficking and sorting during early endocytosis and autophagosome maturation, and abnormalities in these processes are linked to cancers, neurodegeneration, deafness, and hypertropic cardiomyopathy. We identify a structured domain in myosin VI, myosin VI ubiquitin-binding domain (MyUb), that binds to ubiquitin chains, especially those linked via K63, K11, and K29. Herein, we solve the solution structure of MyUb and MyUb:K63-linked diubiquitin. MyUb folds as a compact helix-turn-helix-like motif and nestles between the ubiquitins of K63-linked diubiquitin, interacting with distinct surfaces of each. A nine-amino-acid extension at the C-terminal helix (Helix2) of MyUb is required for myosin VI interaction with endocytic and autophagic adaptors. Structure-guided mutations revealed that a functional MyUb is necessary for optineurin interaction. In addition, we found that an isoform-specific helix restricts MyUb binding to ubiquitin chains. This work provides fundamental insights into myosin VI interaction with ubiquitinated cargo and functional adaptors.

Diverse functions of myosin VI elucidated by an isoform-specific α-helix domain

Myosin VI functions in endocytosis and cell motility. Alternative splicing of myosin VI mRNA generates two distinct isoform types, myosin VI_short and myosin VI_long, which differ in the C-terminal region. Their physiological and pathological role remains unknown. Here we identified an isoform-specific regulatory helix, named α2-linker that defines specific conformations and hence determines the target selectivity of human myosin VI. The presence of the α2-linker structurally defines a novel clathrin-binding domain that is unique to myosin VI_long and masks the known RRL interaction motif. This finding is relevant to ovarian cancer, where alternative myosin VI splicing is aberrantly regulated, and exon skipping dictates cell addiction to myosin VI_short for tumor cell migration. The RRL interactor optineurin contributes to this process by selectively binding myosin VI_short. Thus the α2-linker acts like a molecular switch that assigns myosin VI to distinct endocytic (myosin VI_long) or migratory (myosin VI_short) functional roles.

Liprin-α1, ERC1 and LL5 identify a polarized, dynamic compartment implicated in cell migration

Cell migration during development and metastatic invasion requires the coordination of actin and adhesion dynamics to promote the protrusive activity at the cell front. The knowledge of the molecular mechanisms required to achieve such coordination is fragmentary. Here we identify a new functional complex that drives cell motility. The adaptor proteins ERC1a and LL5 are required with liprin-α1 for effective migration and tumor cell invasion, and do so by stabilizing the protrusive activity at the cell front. Depletion of either protein negatively affects invasion, migration on extracellular matrix, lamellipodial persistence, as well as the internalization of active integrin β1 receptors needed for adhesion turnover at the cell front. Liprin-α1, ERC1a and LL5 also define new highly polarized and dynamic cytoplasmic structures uniquely localized near the protruding cell edge. Our results indicate that the functional complex and the associated structures described here represent an important mechanism to drive tumor cell migration.