RAB7L1-Mediated Relocalization of LRRK2 to the Golgi Complex Causes Centrosomal Deficits via RAB8A

Mutations in the LRRK2 gene cause autosomal-dominant Parkinson’s disease (PD), and both LRRK2 as well as RAB7L1 have been implicated in increased susceptibility to idiopathic PD. RAB7L1 has been shown to increase membrane-association and kinase activity of LRRK2, and both seem to be mechanistically implicated in the same pathway. Another RAB protein, RAB8A, has been identified as a prominent LRRK2 kinase substrate, and our recent work demonstrates that aberrant LRRK2-mediated phosphorylation of RAB8A leads to centrosomal alterations. Here, we show that RAB7L1 recruits LRRK2 to the Golgi complex, which causes accumulation of phosphorylated RAB8A in a pericentrosomal/centrosomal location as well as centrosomal deficits identical to those observed with pathogenic LRRK2. The centrosomal alterations induced by wildtype LRRK2 in the presence of RAB7L1 depend on Golgi integrity. This is in contrast to pathogenic LRRK2 mutants, which cause centrosomal deficits independent of Golgi integrity or largely independent on RAB7L1 expression. Furthermore, centrosomal alterations in the presence of wildtype LRRK2 and RAB7L1 are at least in part mediated by aberrant LRRK2-mediated RAB8A phosphorylation, as abolished by kinase inhibitors and reduced upon knockdown of RAB8A. These results indicate that pathogenic LRRK2, as well as increased levels of RAB7L1, cause centrosomal deficits in a manner dependent on aberrant RAB8A phosphorylation and centrosomal/pericentrosomal accumulation, suggesting that centrosomal cohesion deficits may comprise a useful cellular readout for a broader spectrum of the disease

Cellular effects mediated by pathogenic LRRK2: homing in on Rab-mediated processes

Leucine-rich repeat kinase 2 (LRRK2) is a key player in the pathogenesis of Parkinson's disease. Mutations in LRRK2 are associated with increased kinase activity that correlates with cytotoxicity, indicating that kinase inhibitors may comprise promising diseasemodifying compounds. However, before embarking on such strategies, detailed knowledge of the cellular deficits mediated by pathogenic LRRK2 in the context of defined and pathologically relevant kinase substrates is essential. LRRK2 has been consistently shown to impair various intracellular vesicular trafficking events, and recent studies have shown that LRRK2 can phosphorylate a subset of proteins that are intricately implicated in those processes. In light of these findings, we here review the link between cellular deficits in intracellular trafficking pathways and the LRRK2-mediated phosphorylation of those newly identified substrates

Pathogenic LRRK2 regulates centrosome cohesion via Rab10/RILPL1-mediated CDK5RAP2 displacement

Mutations in LRRK2 increase its kinase activity and cause Parkinson's disease. LRRK2 phosphorylates a subset of Rab proteins which allows for their binding to RILPL1. The phospho-Rab/RILPL1 interaction causes deficits in ciliogenesis and interferes with the cohesion of duplicated centrosomes. We show here that centrosomal deficits mediated by pathogenic LRRK2 can also be observed in patient-derived iPS cells, and we have used transiently transfected cell lines to identify the underlying mechanism. The LRRK2-mediated centrosomal cohesion deficits are dependent on both the GTP conformation and phosphorylation status of the Rab proteins. Pathogenic LRRK2 does not displace proteinaceous linker proteins which hold duplicated centrosomes together, but causes the centrosomal displacement of CDK5RAP2, a protein critical for centrosome cohesion. The LRRK2-mediated centrosomal displacement of CDK5RAP2 requires RILPL1 and phospho-Rab proteins, which stably associate with centrosomes. These data provide fundamental information as to how pathogenic LRRK2 alters the normal physiology of a cell.We are grateful to Erich Nigg and Francis Barr for providing a variety of constructs and antibodies, and to Dario Alessi for providing various A549 cell lines and MEF cells. We thank LauraMontosa for excellent technical assistance with confocal microscopy. This work was supported by The Michael J. Fox Foundation for Parkinson's research (to S.H.), intramural funding from Rutgers University (to S.H.), the Spanish Ministry of Economy and Competitiveness (SAF2017-89402-R to S.H.), the BBVA Foundation (to S.H., S.A.C., and R.W. M.), the Spanish Ministry of Education, Culture and Sport (FPU12/04367 to J.M. P., FPU15/05233 to A.J. L.O.), and the Spanish Ministry of Science, Innovation and Universities (EST18/00412 to A.J.L. O.)

Immigrant IBD Patients in Spain Are Younger, Have More Extraintestinal Manifestations and Use More Biologics Than Native Patients

BackgroundPrevious studies comparing immigrant ethnic groups and native patients with IBD have yielded clinical and phenotypic differences. To date, no study has focused on the immigrant IBD population in Spain. MethodsProspective, observational, multicenter study comparing cohorts of IBD patients from ENEIDA-registry who were born outside Spain with a cohort of native patients. ResultsWe included 13,524 patients (1,864 immigrant and 11,660 native). The immigrants were younger (45 +/- 12 vs. 54 +/- 16 years, p < 0.001), had been diagnosed younger (31 +/- 12 vs. 36 +/- 15 years, p < 0.001), and had a shorter disease duration (14 +/- 7 vs. 18 +/- 8 years, p < 0.001) than native patients. Family history of IBD (9 vs. 14%, p < 0.001) and smoking (30 vs. 40%, p < 0.001) were more frequent among native patients. The most prevalent ethnic groups among immigrants were Caucasian (41.5%), followed by Latin American (30.8%), Arab (18.3%), and Asian (6.7%). Extraintestinal manifestations, mainly musculoskeletal affections, were more frequent in immigrants (19 vs. 11%, p < 0.001). Use of biologics, mainly anti-TNF, was greater in immigrants (36 vs. 29%, p < 0.001). The risk of having extraintestinal manifestations [OR: 2.23 (1.92-2.58, p < 0.001)] and using biologics [OR: 1.13 (1.0-1.26, p = 0.042)] was independently associated with immigrant status in the multivariate analyses. ConclusionsCompared with native-born patients, first-generation-immigrant IBD patients in Spain were younger at disease onset and showed an increased risk of having extraintestinal manifestations and using biologics. Our study suggests a featured phenotype of immigrant IBD patients in Spain, and constitutes a new landmark in the epidemiological characterization of immigrant IBD populations in Southern Europe

Centrosomal defects caused by the Parkinson’s disease associated protein kinase LRRK2 and Rab proteins

Mutations in the leucine rich repeat kinase 2 (LRRK2) gene are the most common cause of familial Parkinson’s disease (PD), with autosomal-dominant inheritance, and variants in this gene also confer risk to develop sporadic PD. Whilst the cellular and molecular mechanisms underlying LRRK2-PD remain largely unknown, recent studies have identified a subset of Rab GTPases as physiological LRRK2 kinase substrates. In the present study, we identify centrosomal alterations caused by pathogenic LRRK2 using different cell lines and confirmed in patient-derived samples. In non-dividing cells, pathogenic LRRK2 causes deficits in centrosome positioning with downstream consequences for cell differentiation, polarity and directional migration. In dividing cells, pathogenic LRRK2 causes centrosomal cohesion defects. Importantly, we demonstrate that these defects are dependent on the LRRK2 kinase activity. We confirm that Rab8a, a small Rab GTPase with described roles in centrosome-related events, is a LRRK2 kinase substrate, and corroborate that pathogenic LRRK2 increases Rab8a phosphorylation. For the first time, we identify the cellular localization and consequences of LRRK2-mediated Rab8a phosphorylation. We demonstrate that pathogenic LRRK2 causes an abnormal accumulation of phosphorylated Rab8a around the centrosome, which is, at least partially, responsible for the centrosomal cohesion defects. We also evaluate the effects of Rab7L1, a gene that modifies risk for sporadic PD, on the centrosome phenotype. Remarkably, we observe that when increasing Rab7L1 levels, wildtype LRRK2 mimicks the effects of pathogenic LRRK2 on Rab8a phosphorylation and centrosomal cohesion deficits, suggesting that both phenotypes may be a common readout for a broader spectrum of PD. Whilst the downstream consequences of the centrosomal defects and its relevance for PD remain to be elucidated, the data presented here identify a new role for LRRK2 in the context of centrosomal functioning, and indicate the important role of Rab proteins for understanding PD pathogenesis.Las mutaciones en el gen leucine rich repeat kinase 2 (LRRK2) son la causa más común de la enfermedad de Parkinson (EP) hereditaria, presentando una herencia autosómica dominante. Además, otras variantes en LRRK2 se han visto asociadas a un mayor riesgo de sufrir EP esporádica, sugiriendo que LRRK2 desempeña un papel importante y general en la EP. Aunque todavía desconocemos los mecanismos celulares y moleculares que subyacen a la EP, recientemente se han descubierto un subgrupo de proteínas de la familia de las Rab GTPasas como sustratos fisiológicos de la actividad quinasa de LRRK2. En este trabajo, hemos identificado que LRRK2 patogénico causa alteraciones en el centrosoma, usando diferentes líneas celulares y comprobadas en muestras derivadas de pacientes. Por una parte, en células que no se dividen, LRRK2 patogénico causa alteraciones en el posicionamiento del centrosoma, con consecuencias en la capacidad de las células para diferenciarse, polarizarse y migrar. Por otra parte, en células en división, LRRK2 patogénico provoca defectos de cohesión en el centrosoma. De manera significativa, hemos demostrado que dichas alteraciones centrosomales son dependientes de la actividad quinasa de LRRK2. Conjuntamente, hemos confirmado que Rab8a, una pequeña Rab GTPasa con funciones relacionadas a algunos procesos del centrosoma, es un sustrato de LRRK2, y además hemos comprobado que LRRK2 mutante aumenta dicha fosforilación. Por primera vez, hemos identificado la localización y las consecuencias de la fosforilación de Rab8a. En concreto, LRRK2 patogénico provoca una acumulación de Rab8a fosforilado alrededor del centrosoma, lo que es, al menos en parte, responsable de las alteraciones centrosomales descritas. Además, hemos evaluado el papel de Rab7L1, un gen que modifica el riesgo de desarrollar EP, en los problemas centrosomales. Notablemente, observamos que al aumentar los niveles de Rab7L1, la proteína LRRK2 silvestre se comporta como las versiones patogénicas de LRRK2, causando un aumento en la fosforilación de Rab8a y alteraciones en el centrosoma, lo que sugiere que ambos fenotipos pueden ser habituales en un espectro más amplio de la EP. Aunque las consecuencias y la relevancia para la EP de las alteraciones en el centrosoma tienen que ser estudiadas en detalle, este trabajo describe nuevas funciones de la proteína LRRK2 en relación con el centrosoma, y demuestran la importancia de las proteínas Rab en el estudio y comprensión de la EP.Tesis Univ. Granada

Effect of iron chlorosis on mineral nutrition and lipid composition of thylakoid biomembrane in Prunus persica (L.) Bastch

The effect of iron chlorosis on mineral, thylakoid lipids and fatty acids composition of field grown peach tree leaves was studied. Significant differences were found in iron extracted by using α, α′-dipyridyl (active iron), total iron, P, K, Cu and the P/Fe and Fe/Mn ratios. The levels of total chlorophyll, total glycolipids and phospholipids were reduced under iron chlorosis. A slight iron deficiency does not modify the fatty acid composition of thylakoid membranes, while a strong deficiency changes the proportion of some fatty acids.Work was carriedout under the following research projects CICYT AGR90-0792 and CONAI-DGA: PCA-4/91.Peer Reviewe

Cellular effects mediated by pathogenic LRRK2: homing in on Rab-mediated processes

Leucine-rich repeat kinase 2 (LRRK2) is a key player in the pathogenesis of Parkinson's disease. Mutations in LRRK2 are associated with increased kinase activity that correlates with cytotoxicity, indicating that kinase inhibitors may comprise promising disease-modifying compounds. However, before embarking on such strategies, detailed knowledge of the cellular deficits mediated by pathogenic LRRK2 in the context of defined and pathologically relevant kinase substrates is essential. LRRK2 has been consistently shown to impair various intracellular vesicular trafficking events, and recent studies have shown that LRRK2 can phosphorylate a subset of proteins that are intricately implicated in those processes. In light of these findings, we here review the link between cellular deficits in intracellular trafficking pathways and the LRRK2-mediated phosphorylation of those newly identified substrates.Work in the laboratory is supported by FEDER, grants from the Spanish Ministry of Economy and Competitiveness [grant no. SAF2014-58653-R], the Banco Bilbao Vizcaya Argentaria (BBVA) Foundation and the Michael J. Fox Foundation (MJFF).Peer reviewe

LRRK2 and Parkinson's Disease: From Lack of Structure to Gain of Function

Mutations in LRRK2 comprise the most common cause for familial Parkinson's disease (PD), and variations increase risk for sporadic disease, implicating LRRK2 in the entire disease spectrum. LRRK2 is a large protein harbouring both GTPase and kinase domains which display measurable catalytic activity. Most pathogenic mutations increase the kinase activity, with increased activity being cytotoxic under certain conditions. These findings have spurred great interest in drug development approaches, and various specific LRRK2 kinase inhibitors have been developed. However, LRRK2 is a largely ubiquitously expressed protein, and inhibiting its function in some non-neuronal tissues has raised safety liability issues for kinase inhibitor approaches. Therefore, understanding the cellular and cell type-specific role(s) of LRRK2 has become of paramount importance. This review will highlight current knowledge on the precise biochemical activities of normal and pathogenic LRRK2, and highlight the most common proposed cellular roles so as to gain a better understanding of the cell type-specific effects of LRRK2 modulators.Work in the laboratory is funded by FEDER, the Spanish Ministry of Economy and Competitiveness (SAF2014-58653-R), the Junta de Andalucia (CTS-6816), the BBVA Foundation and the Michael J. Fox Foundation. B.F. was funded by a Juan de la Cierva Fellowship (MINECO; JCI2010-07703).Peer reviewe

El México de hoy. Sus grandes problemas y qué hacer frente a ellos

Este libro intenta ofrecer al lector un resumen de lo que son hoy los grandes problemas de México, a fin de disponer de elementos que ayuden a enfrentarnos a ellos con éxito. Cuando se habla de tales problemas se incurre a menudo en una falla que esperamos no esté presente en estas páginas. Consiste esa falla en que, o bien no se repara en los cambios, a veces muy importantes, que el país está viviendo, o bien, tiende a menospreciárseles y se les examina de manera muy parcial, y como si todo siguiera siendo igual que antes. Proceder así, impide a nuestro juicio entender la dinámica central del proceso de desarrollo, y por tanto los hechos de diferente naturaleza que determinan estos problemas. Y como lo que se busca es pprecisamente conocer sus causas principales y atacarlas de nuevas y más eficaces maneras, ésa es la razón por la que el análisis trata de no quedarse en el plano de las políticas conservadoras casi siempre de corto plazo y alcance, con las que se les hace frente. Ellector dirá si lo conseguimos o no