iRhom2 regulates ERBB signalling to promote KRAS-driven tumour growth of lung cancer cells.

Dysregulation of the ERBB/EGFR signalling pathway causes multiple types of cancer. Accordingly, ADAM17, the primary shedding enzyme that releases and activates ERBB ligands, is tightly regulated. It has recently become clear that iRhom proteins, inactive members of the rhomboid-like superfamily, are regulatory cofactors for ADAM17.

Conformational surveillance of Orai1 by a rhomboid intramembrane protease prevents inappropriate CRAC channel activation.

Calcium influx through plasma membrane calcium release-activated calcium (CRAC) channels, which are formed of hexamers of Orai1, is a potent trigger for many important biological processes, most notably in T cell-mediated immunity. Through a bioinformatics-led cell biological screen, we have identified Orai1 as a substrate for the rhomboid intramembrane protease RHBDL2. We show that RHBDL2 prevents stochastic calcium signaling in unstimulated cells through conformational surveillance and cleavage of inappropriately activated Orai1.

Bacterial rhomboid proteases mediate quality control of orphan membrane proteins.

Although multiprotein membrane complexes play crucial roles in bacterial physiology and virulence, the mechanisms governing their quality control remain incompletely understood. In particular, it is not known how unincorporated, orphan components of protein complexes are recognised and eliminated from membranes. Rhomboids, the most widespread and largest superfamily of intramembrane proteases, are known to play key roles in eukaryotes.

FRMD8 promotes inflammatory and growth factor signalling by stabilising the iRhom/ADAM17 sheddase complex.

Many intercellular signals are synthesised as transmembrane precursors that are released by proteolytic cleavage ('shedding') from the cell surface. ADAM17, a membrane-tethered metalloprotease, is the primary shedding enzyme responsible for the release of the inflammatory cytokine TNFα and several EGF receptor ligands. ADAM17 exists in complex with the rhomboid-like iRhom proteins, which act as cofactors that regulate ADAM17 substrate shedding.

A Simple Cell-Based Assay for the Detection of Surface Protein Shedding by Rhomboid Proteases.

Rhomboids are intramembrane serine proteases that cleave their substrates within or immediately adjacent to their transmembrane domains, a process known as regulated intramembrane proteolysis. In eukaryotes, two main types of rhomboid proteases can be distinguished based on their subcellular localization: mitochondrial rhomboids and secretase-type rhomboids that target the secretory pathway. The latter class can cleave and release the extracellular domain of all epidermal growth factor-like proteins in Drosophila and can liberate epidermal growth factor (EGF) in mammals, in a process known as ectodomain shedding.

Phosphorylation of iRhom2 at the plasma membrane controls mammalian TACE-dependent inflammatory and growth factor signalling.

Proteolytic cleavage and release from the cell surface of membrane-tethered ligands is an important mechanism of regulating intercellular signalling. TACE is a major shedding protease, responsible for the liberation of the inflammatory cytokine TNFα and ligands of the epidermal growth factor receptor. iRhoms, catalytically inactive members of the rhomboid-like superfamily, have been shown to control the ER-to-Golgi transport and maturation of TACE.

Substrates and physiological functions of secretase rhomboid proteases.

Rhomboids are conserved intramembrane serine proteases with widespread functions. They were the earliest discovered members of the wider rhomboid-like superfamily of proteases and pseudoproteases. The secretase class of rhomboid proteases, distributed through the secretory pathway, are the most numerous in eukaryotes, but our knowledge of them is limited.

The F-BAR protein pacsin2 inhibits asymmetric VE-cadherin internalization from tensile adherens junctions.

Vascular homoeostasis, development and disease critically depend on the regulation of endothelial cell-cell junctions. Here we uncover a new role for the F-BAR protein pacsin2 in the control of VE-cadherin-based endothelial adhesion. Pacsin2 concentrates at focal adherens junctions (FAJs) that are experiencing unbalanced actomyosin-based pulling.

Genetic interaction implicates iRhom2 in the regulation of EGF receptor signalling in mice.

iRhoms are closely related to rhomboid intramembrane proteases but lack catalytic activity. In mammals iRhoms are known to regulate the trafficking of TACE, the protease that cleaves the membrane bound inflammatory cytokine TNF. We have mapped a spontaneously occurring mouse mutation with a loss of hair phenotype, curly bare (cub), to the Rhbdf2 locus, which encodes the iRhom2 protein.

Extracellular cleavage of E-cadherin promotes epithelial cell extrusion.

Epithelial cell extrusion and subsequent apoptosis is a key mechanism to prevent the accumulation of excess cells. By contrast, when driven by oncogene expression, apical cell extrusion is followed by proliferation and represents an initial step of tumorigenesis. E-cadherin (E-cad), the main component of adherens junctions, has been shown to be essential for epithelial cell extrusion, but its mechanistic contribution remains unclear.

GRASP65 controls the cis Golgi integrity in vivo.

GRASP65 and GRASP55 are peripheral Golgi proteins localized to cis and medial/trans cisternae, respectively. They are implicated in diverse aspects of protein transport and structure related to the Golgi complex, including the stacking of the Golgi stack and/or the linking of mammalian Golgi stacks into the Golgi ribbon. Using a mouse model, we interfered with GRASP65 by homologous recombination and confirmed its absence of expression.

Long-term follow-up of cystic fibrosis newborn screening: psychosocial functioning of adolescents and young adults.

Background: Long-term psychosocial outcomes of cystic fibrosis (CF) patients diagnosed through newborn screening remain unknown.

Methods: This cross-sectional study compared three groups of youths (16 to 22 years): CF patients diagnosed through NBS (CF-NBS, n = 13), CF patients diagnosed through standard practice (CF-SP, n = 26) and healthy peers (H, n = 42), plus 72 of their parents. We hypothesized that adolescent psychological functioning would be mediated by parent depression and quality of parent-child communication and cohesiveness.

Health-related quality of life in children and adolescents with cystic fibrosis: convergent validity with parent-reports and objective measures of pulmonary health.

Objective: This study examined the convergent validity of health-related quality of life (HRQOL) reported by patients with cystic fibrosis compared with their parents' reports and objective pulmonary measures across 3 time points.

Methods: Ninety-two children (8-13 years) and adolescents (14-18 years) with cystic fibrosis and their parents completed Cystic Fibrosis Questionnaires to examine concordance with Wisconsin chest x-ray (WCXR) scores and pulmonary function tests, for example, forced expiratory volume at 1 second (FEV1), and parent-child/adolescent concordance across multiple HRQOL domains. Concordance was analyzed relative to patient age and gender.

Neurocognitive function and state cognitive stress appraisal predict cortisol reactivity to an acute psychosocial stressor in adolescents.

Stress and associated alterations in hypothalamic-pituitary-adrenal (HPA) function have deleterious influence on the development of multiple mental and physical health problems. Prior research has aimed to identify individuals most at risk for the development of these stress-related maladies by examining factors that may contribute to inter-individual differences in HPA responses to acute stress. The objectives of this study were to investigate, in adolescents, (1) whether differences in neurocognitive abilities influenced cortisol reactivity to an acute stressor, (2) whether internalizing psychiatric disorders influenced this relationship, and (3) whether acute cognitive stress-appraisal mechanisms mediated an association between neurocognitive function and cortisol reactivity.

Annexin A2 at the interface of actin and membrane dynamics: a focus on its roles in endocytosis and cell polarization.

Annexins are a family of calcium- and phospholipid-binding proteins found in nearly all eukaryotes. They are structurally highly conserved and have been implicated in a wide range of cellular activities. In this paper, we focus on Annexin A2 (AnxA2).

Associations between academic achievement and psychosocial variables in adolescents with cystic fibrosis.

Background: Cystic fibrosis (CF) is a chronic genetic disease that leads to the accumulation of thick mucus in multiple organ systems, leading to chronic lung infection and affecting the body's ability to absorb nutrients necessary for growth and development. This cross-sectional, correlational study examined the potential effects of CF on students' psychosocial and academic development.

Methods: Forty adolescents with CF completed a battery of neuropsychological and psychosocial measures.

Lowe Syndrome protein OCRL1 supports maturation of polarized epithelial cells.

Mutations in the inositol polyphosphate 5-phosphatase OCRL1 cause Lowe Syndrome, leading to cataracts, mental retardation and renal failure. We noted that cell types affected in Lowe Syndrome are highly polarized, and therefore we studied OCRL1 in epithelial cells as they mature from isolated individual cells into polarized sheets and cysts with extensive communication between neighbouring cells. We show that a proportion of OCRL1 targets intercellular junctions at the early stages of their formation, co-localizing both with adherens junctional components and with tight junctional components.

Unconventional secretion: a stress on GRASP.

Most proteins follow the classical secretory pathway from the endoplasmic reticulum, via the Golgi, to the plasma membrane or extracellular medium. However, some proteins reach these final destinations by two alternative routes. One sustains the extracellular delivery of cytoplasmic proteins that lack a signal peptide, the other supports the transport of transmembrane proteins to the plasma membrane in a manner that bypasses the Golgi.

Golgi bypass: skirting around the heart of classical secretion.

Classical secretion consists of the delivery of transmembrane and soluble proteins to the plasma membrane and the extracellular medium, respectively, and is mediated by the organelles of the secretory pathway, the Endoplasmic Reticulum (ER), the ER exit sites, and the Golgi, as described by the Nobel Prize winner George Palade (Palade 1975). At the center of this transport route, the Golgi stack has a major role in modifying, processing, sorting, and dispatching newly synthesized proteins to their final destinations. More recently, however, it has become clear that an increasing number of transmembrane proteins reach the plasma membrane unconventionally, either by exiting the ER in non-COPII vesicles or by bypassing the Golgi.

The multiple facets of the Golgi reassembly stacking proteins.

The mammalian GRASPs (Golgi reassembly stacking proteins) GRASP65 and GRASP55 were first discovered more than a decade ago as factors involved in the stacking of Golgi cisternae. Since then, orthologues have been identified in many different organisms and GRASPs have been assigned new roles that may seem disconnected. In vitro, GRASPs have been shown to have the biochemical properties of Golgi stacking factors, but the jury is still out as to whether they act as such in vivo.

Annexin A2 at the interface between F-actin and membranes enriched in phosphatidylinositol 4,5,-bisphosphate.

Vesicle rocketing has been used as a model system for understanding the dynamics of the membrane-associated F-actin cytoskeleton, but in many experimental systems is induced by persistent, non-physiological stimuli. Localised changes in the concentration of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) in membranes stimulate the recruitment of actin-remodelling proteins to their sites of action, regulate their activity and favour vesicle rocketing. The calcium and anionic phospholipid-binding protein annexin A2 is necessary for macropinocytic rocketing and has been shown to bind both PI(4,5)P2 and the barbed-ends of F-actin filaments.

A prospective, open-label trial of memantine in the treatment of cognitive, behavioral, and memory dysfunction in pervasive developmental disorders.

Background: This pilot study examined the effectiveness of memantine hydrochloride in improving cognitive functioning and behavioral symptoms in children with pervasive developmental disorders (PDDs).

Method: Subjects aged 3-12 years inclusive were enrolled in this 8-week, open-label study. Expressive and receptive language, nonverbal IQ, and nonverbal memory measures were administered at baseline and after 8 weeks of treatment with 0.