Primary cilia are sensory membrane protrusions whose dysfunction causes ciliopathies. INPP5E is a ciliary phosphoinositide phosphatase mutated in ciliopathies like Joubert syndrome. INPP5E regulates ...numerous ciliary functions, but how it accumulates in cilia remains poorly understood. Herein, we show INPP5E ciliary targeting requires its folded catalytic domain and is controlled by four conserved ciliary localization signals (CLSs): LLxPIR motif (CLS1), W383 (CLS2), FDRxLYL motif (CLS3) and CaaX box (CLS4). We answer two long-standing questions in the field. First, partial CLS1-CLS4 redundancy explains why CLS4 is dispensable for ciliary targeting. Second, the essential need for CLS2 clarifies why CLS3-CLS4 are together insufficient for ciliary accumulation. Furthermore, we reveal that some Joubert syndrome mutations perturb INPP5E ciliary targeting, and clarify how each CLS works: (i) CLS4 recruits PDE6D, RPGR and ARL13B, (ii) CLS2-CLS3 regulate association to TULP3, ARL13B, and CEP164, and (iii) CLS1 and CLS4 cooperate in ATG16L1 binding. Altogether, we shed light on the mechanisms of INPP5E ciliary targeting, revealing a complexity without known parallels among ciliary cargoes.
Chromatin is the template for the basic processes of replication and transcription, making the maintenance of chromosomal integrity critical for cell viability. To elucidate how dividing cells ...respond to alterations in chromatin structure, here we analyse the replication programme of primary cells with altered chromatin configuration caused by the genetic ablation of the HMGB1 gene, or three histone H1 genes. We find that loss of chromatin compaction in H1-depleted cells triggers the accumulation of stalled forks and DNA damage as a consequence of transcription-replication conflicts. In contrast, reductions in nucleosome occupancy due to the lack of HMGB1 cause faster fork progression without impacting the initiation landscape or fork stability. Thus, perturbations in chromatin integrity elicit a range of responses in the dynamics of DNA replication and transcription, with different consequences on replicative stress. These findings have broad implications for our understanding of how defects in chromatin structure contribute to genomic instability.
Generalized lymphatic anomaly (GLA) is a vascular disorder characterized by diffuse or multifocal lymphatic malformations (LMs). The etiology of GLA is poorly understood. We identified four distinct ...somatic
variants (Glu542Lys, Gln546Lys, His1047Arg, and His1047Leu) in tissue samples from five out of nine patients with GLA. These same
variants occur in
-related overgrowth spectrum and cause hyperactivation of the PI3K-AKT-mTOR pathway. We found that the mTOR inhibitor, rapamycin, prevented lymphatic hyperplasia and dysfunction in mice that expressed an active form of
(His1047Arg) in their lymphatics. We also found that rapamycin reduced pain in patients with GLA. In conclusion, we report that somatic activating
mutations can cause GLA, and we provide preclinical and clinical evidence to support the use of rapamycin for the treatment of this disabling and deadly disease.
In the dominant model, monozygotic (MZ) twinning is universally accepted as a post-fertilization event resulting from splitting of the embryo along its first 2 weeks of development. The stage at ...which splitting occurs determines chorionicity and amnionicity. A short history on how the model was built is presented, stressing the role played by some embryologists, in particular George Corner, in its completion and final success. Strikingly, for more than 60 years no deep criticisms have been raised against the model, which, in virtue of its rational and plausible character, enjoys the status of undisputed truth. At close examination, the embryological support of the model shows some important weak points, particularly when dealing with late splitting. In the author's view, the model not only has contributed to 'suspend' our knowledge on the timing of MZ twinning, but seems indefensible and claims to be substituted. That factor could imply relevant consequences for embryology and bioethics. As an alternative to the model, a new theory to explain the timing of MZ twinning is proposed. It is based on two premises. First, MZ twinning would be a fertilization event. In that case, due to an alteration of the zygote-blastomere transition, the first zygotic division, instead of producing two blastomeres, generates twin zygotes. Second, monochorionicity and monoamnionicity would not depend on embryo splitting, but on fusion of membranes. Some support for this theory can be found in recent embryological advances and also in some explanations of old.
Multivesicular bodies (MVB) are endocytic compartments that enclose intraluminal vesicles (ILVs) formed by inward budding from the limiting membrane of endosomes. In T lymphocytes, ILVs are secreted ...as Fas ligand-bearing, pro-apoptotic exosomes following T cell receptor (TCR)-induced fusion of MVB with the plasma membrane at the immune synapse (IS). In this study we show that protein kinase C δ (PKCδ), a novel PKC isotype activated by diacylglycerol (DAG), regulates TCR-controlled MVB polarization toward the IS and exosome secretion. Concomitantly, we demonstrate that PKCδ-interfered T lymphocytes are defective in activation-induced cell death. Using a DAG sensor based on the C1 DAG-binding domain of PKCδ and a GFP-PKCδ chimera, we reveal that T lymphocyte activation enhances DAG levels at the MVB endomembranes which mediates the association of PKCδ to MVB. Spatiotemporal reorganization of F-actin at the IS is inhibited in PKCδ-interfered T lymphocytes. Therefore, we propose PKCδ as a DAG effector that regulates the actin reorganization necessary for MVB traffic and exosome secretion.
This study examines value similarities between deviant youth on the one hand and mainstream society on the other rather than value differences. The classic sociological research on deviance by Matza ...and Sykes supports this approach, given that their investigations focused more on similarities between subterranean values and the values of normal society. The General Social Survey of Spain (2016) includes 17 indicators for deviant behavior, which is the dependent variable. Likewise, it is used to define social capital and the rest of the different independent variables of the analysis. In conclusion, whereas social capital and social values were absent as causes of juvenile delinquency, the following variables explained significantly the deviant behavior among Spanish youth: tolerance towards deviance, adolescent experience, and sex. This suggests that there are at least two possible keys to improve or avoid the problem of juvenile crime: prevention or awareness programmes and new critical feminist criminology point of view.
This article reviews the research on the factors influencing victimization and explores the case of Spain. The first section presents a comparative analysis of the data for 1999 and 2016 in terms of ...perceptions, profiles and the most significant sociodemographic and socioeconomic variables. The second section shows an explanatory analysis based on multivariate logistical regression models, using as independent variables sociodemographic and psychosocial items, and the dependent variable is whether one is described as one is described as a victim or no in the 2016 survey. The results point towards an explanatory model of victimization in which sociodemographic variables play a less important role, whereas psychosocial variables related to lifestyle and subjective perceptions make a significant contribution to greater understanding of the nature of being the victim of a crime and offer suggestions on how to improve Crime Prevention Through Environmental Design (CPTED).
T-cell receptor stimulation induces the convergence of multivesicular bodies towards the microtubule-organizing centre (MTOC) and the polarization of the MTOC to the immune synapse (IS). These events ...lead to exosome secretion at the IS. We describe here that upon IS formation centrosomal area F-actin decreased concomitantly with MTOC polarization to the IS. PKCδ-interfered T cell clones showed a sustained level of centrosomal area F-actin associated with defective MTOC polarization. We analysed the contribution of two actin cytoskeleton-regulatory proteins, FMNL1 and paxillin, to the regulation of cortical and centrosomal F-actin networks. FMNL1
phosphorylation and F-actin reorganization at the IS were inhibited in PKCδ-interfered clones. F-actin depletion at the central region of the IS, a requirement for MTOC polarization, was associated with FMNL1
phosphorylation at its C-terminal, autoregulatory region. Interfering all FMNL1 isoforms prevented MTOC polarization; nonetheless, FMNL1
re-expression restored MTOC polarization in a centrosomal area F-actin reorganization-independent manner. Moreover, PKCδ-interfered clones exhibited decreased paxillin phosphorylation at the MTOC, which suggests an alternative actin cytoskeleton regulatory pathway. Our results infer that PKCδ regulates MTOC polarization and secretory traffic leading to exosome secretion in a coordinated manner by means of two distinct pathways, one involving FMNL1
regulation and controlling F-actin reorganization at the IS, and the other, comprising paxillin phosphorylation potentially controlling centrosomal area F-actin reorganization.
Ab, antibody; AICD, activation-induced cell death; AIP, average intensity projection; APC, antigen-presenting cell; BCR, B-cell receptor for antigen;
C
, centre of mass; cent2, centrin 2; cIS, central region of the immune synapse; CMAC, CellTracker™ Blue (7-amino-4-chloromethylcoumarin); cSMAC, central supramolecular activation cluster; CTL, cytotoxic T lymphocytes; DAG, diacylglycerol; DGKα, diacylglycerol kinase α; Dia1, Diaphanous-1; dSMAC, distal supramolecular activation cluster; ECL, enhanced chemiluminescence; ESCRT, endosomal sorting complex required for traffic; F-actin, filamentous actin; Fact-low cIS, F-actin-low region at the centre of the immune synapse; FasL, Fas ligand; FMNL1, formin-like 1; fps, frames per second; GFP, green fluorescent protein; HBSS, Hank's balanced salt solution; HRP, horseradish peroxidase; ILV, intraluminal vesicles; IS, immune synapse; MFI, mean fluorescence intensity; MHC, major histocompatibility complex; MIP, maximal intensity projection; MVB, multivesicular bodies; MTOC, microtubule-organizing centre; NS, not significant; PBL, peripheral blood lymphocytes; PKC, protein kinase C; PKCδ, protein kinase C δ isoform; PLC, phospholipase C; PMA, phorbol myristate acetate; Pol. Index, polarization index; pSMAC, peripheral supramolecular activation cluster; PSF, point spread function; ROI, region of interest; SD, standard deviation; shRNA, short hairpin RNA; SEE, Staphylococcus enterotoxin E; SMAC, supramolecular activation cluster; TCR, T-cell receptor for antigen; T-helper (Th); TRANS, transmittance; WB, Western blot.
Como un homenaje de Persona y Bioética al Dr. Gonzalo Herranz, recientemente fallecido en Pamplona, publicamos el texto de una conferencia suya sobre Bioética y el embrión humano.
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