Endoplasmic reticulum (ER)-associated degradation (ERAD) is required for ubiquitin-mediated destruction of numerous proteins. ERAD occurs by processes on both sides of the ER membrane, including lumenal substrate scanning and cytosolic destruction by the proteasome. The ER resident membrane proteins Hrd1p and Hrd3p play central roles in ERAD. We show that these two proteins directly interact through the Hrd1p transmembrane domain, allowing Hrd1p stability by Hrd3p-dependent control of the Hrd1p RING-H2 domain activity. Rigorous reevaluation of Hrd1p topology demonstrated that the Hrd1p RING-H2 domain is located and functions in the cytosol. An engineered, completely lumenal, truncated version of Hrd3p functioned normally in both ERAD and Hrd1p stabilization, indicating that the lumenal domain of Hrd3p regulates the cytosolic Hrd1p RING-H2 domain by signaling through the Hrd1p transmembrane domain. Additionally, we identified a lumenal region of Hrd3p dispensable for regulation of Hrd1p stability, but absolutely required for normal ERAD. Our studies show that Hrd1p and Hrd3p form a stoichiometric complex with ERAD determinants in both the lumen and the cytosol. The HRD complex engages in lumen to cytosol communication required for regulation of Hrd1p stability and the coordination of ERAD events on both sides of the ER membrane.

KRAS mutations are found in ∼90% of human pancreatic ductal adenocarcinomas (PDAC). However, mice genetically engineered to express Kras G12D from its endogenous locus develop PDACs only after a prolonged latency, indicating that other genetic events or pathway alterations are necessary for PDAC progression. The PTEN-controlled phosphatidylinositol 3-kinase (PI3K)/AKT signaling axis is dysregulated in later stages of PDAC. To better elucidate the role of PTEN/PI3K/AKT signaling in Kras G12D -induced PDAC development, we crossed Pten conditional knockout mice (Pten lox/lox ) to mice with conditional activation of Kras G12D . The resulting compound heterozygous mutant mice showed significantly accelerated development of acinar-to-ductal metaplasia (ADM), malignant pancreatic intraepithelial neoplasia (mPanIN), and PDAC within a year. Moreover, all mice with Kras G12D activation and Pten homozygous deletion succumbed to cancer by 3 weeks of age. Our data support a dosage-dependent role for PTEN, and the resulting dysregulation of the PI3K/AKT signaling axis, in both PDAC initiation and progression, and shed additional light on the signaling mechanisms that lead to the development of ADM and subsequent mPanIN and pancreatic cancer. Cancer Res; 70(18); 7114-24. ©2010 AACR.

We propose a two-step model for the evolutionary origin of the turtle shell. We show here that the carapacial ridge (CR) is critical for the entry of the ribs into the dorsal dermis. Moreover, we demonstrate that the maintenance of the CR and its ability to attract the migrating rib precursor cells depend upon fibroblast growth factor (FGF) signaling. Inhibitors of FGF allow the CR to degenerate, with the consequent migration of ribs along the ventral body wall. Beads containing FGF10 can rearrange rib migration in the chick, suggesting that the CR FGF10 plays an important role in attracting the rib rudiments. The co-ordinated growth of the carapacial plate and the ribs may be a positive feedback loop (similar to that of the limbs) caused by the induction of Fgf8 in the distal tips of the ribs by the FGF10-secreting mesenchyme of the CR. Once in the dermis, the ribs undergo endochrondral ossification. We provide evidence that the ribs act as signaling centers for the dermal ossification and that this ossification is due to bone morphogenetic proteins secreted by the rib. Thus, once the ribs are within the dermis, the ossification of the dermis is not difficult to achieve. This relatively rapid means of carapace formation would allow for the appearance of turtles in the fossil record without obvious intermediates.

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of non-Hodgkin lymphomas frequently associated with poor prognosis and for which genetic mechanisms of transformation remain incompletely understood. Using RNA sequencing and targeted sequencing, here we identify a recurrent in-frame deletion (VAV1 Δ778-786) generated by a focal deletion-driven alternative splicing mechanism as well as novel VAV1 gene fusions (VAV1-THAP4, VAV1-MYO1F, and VAV1-S100A7) in PTCL. Mechanistically these genetic lesions result in increased activation of VAV1 catalytic-dependent (MAPK, JNK) and non-catalytic-dependent (nuclear factor of activated T cells, NFAT) VAV1 effector pathways. These results support a driver oncogenic role for VAV1 signaling in the pathogenesis of PTCL.peripheral T-cell lymphoma | VAV1 | mutation | gene fusion P eripheral T-cell lymphomas (PTCLs) are malignant and highly aggressive hematologic tumors arising from mature postthymic T cells (1). The diagnosis of PTCL includes diverse lymphoma subgroups, altogether accounting for about 15% of all non-Hodgkin lymphomas (2, 3). Despite much effort in developing reliable diagnostic markers, the diagnosis of PTCLs is challenging, and 20 to 30% of cases are diagnosed as PTCL-NOS (not otherwise specified). This heterogeneous and poorly defined group constitutes one of the most aggressive forms of non-Hodgkin lymphoma, in which limited response to intensified chemotherapy and high relapse rates result in a dismal 5-y overall survival rate of 20 to 30% (4, 5). Moreover, a paucity of information on driver oncogenes activated in PTCL-NOS hampers the development of targeted therapies in this aggressive lymphoma subgroup.The VAV1 protooncogene encodes a guanine nucleotide exchange factor (GEF) and adaptor protein with crucial signaling roles in protein tyrosine kinase-regulated pathways (6). Structurally, VAV1 contains a calponin homology domain and an acidic domain in the N terminus followed by a GEF catalytic active core consisting of a central Dbl homology domain, pleckstrin homology domain, and C1 domain (6). Finally, the C-terminal region of VAV1 contains three Src homology domains in an SH3-SH2-SH3 arrangement (6). The GEF activity of VAV1 stimulates the transition of RAC1 and RHOA small GTPases from their inactive (GDP-bound) to the active (GTP-bound) configuration (6-8). In addition, the adaptor function of VAV1 mediates activation of the nuclear factor of activated T cells (NFAT) in synergy with signals from antigenic receptors in lymphoid cells (6,(8)(9)(10)(11)(12)(13). In basal conditions, unphosphorylated VAV1 adopts an inactive closed configuration in which the N-terminal calponin homology and acidic domains and

The state of CENP-E–dependent BubR1 autophosphorylation in response to spindle microtubule capture regulates kinetochore function and accurate chromosome segregation.

One of the greatest advances in Parkinson's disease (PD) research in the past two decades has been a better understanding of PD genetics. Of the many candidate genes investigated, the best studied include and. The authors review the key clinical features of these monogenic forms, as well as for the prevalent risk factor gene, including the phenotype, clinical course, and treatment response. They also outline areas for future investigation: longitudinal studies of PD's clinical course, the identification of its premotor manifestations, and its specific mechanisms of pathogenicity.

Cyclooxygenase-2 (COX-2) is upregulated in pancreatic ductal adenocarcinomas (PDAC). However, how COX-2 promotes PDAC development is unclear. While previous studies have evaluated the efficacy of COX-2 inhibition via the use of non steroidal anti-inflammatory drugs (NSAIDs) or the COX-2 inhibitor celecoxib in PDAC models, none have addressed the cell intrinsic vs. microenvironment roles of COX-2 in modulating PDAC initiation and progression. We tested the cell intrinsic role of COX-2 in PDAC progression, using both loss-of-function and gain-of-function approaches. Cox-2 deletion in Pdx1+ pancreatic progenitor cells significantly delays the development of PDAC in mice with K-ras activation and Pten haploinsufficiency. Conversely, COX-2 over-expression promotes early onset and progression of PDAC in the K-ras mouse model. Loss of PTEN function is a critical factor in determining lethal PDAC onset and overall survival. Mechanistically, COX-2 over-expression increases P-AKT levels in the precursor lesions of Pdx1+;K-rasG12D/+;Ptenlox/+ mice in the absence of Pten LOH. In contrast, Cox-2 deletion in the same setting diminishes P-AKT levels and delays cancer progression. These data suggest an important cell intrinsic role for COX-2 in tumor initiation and progression through activation of the PI3K/AKT pathway. PDAC that is independent of intrinsic COX-2 expression eventually develops with decreased FKBP5 and increased GRP78 expression, two alternate pathways leading to AKT activation. Together, these results support a cell intrinsic role for COX-2 in PDAC development and suggest that, while anti-COX-2 therapy may delay the development and progression of PDAC, mechanisms known to increase chemoresistance through AKT activation must also be overcome.

We report graphitic carbon growth on crystalline and amorphous oxide substrates by using carbon molecular beam epitaxy. The films are characterized by Raman spectroscopy and X-ray photoelectron spectroscopy. The formations of nanocrystalline graphite are observed on silicon dioxide and glass, while mainly sp2 amorphous carbons are formed on strontium titanate and yttria-stabilized zirconia. Interestingly, flat carbon layers with high degree of graphitization are formed even on amorphous oxides. Our results provide a progress toward direct graphene growth on oxide materials.PACS: 81.05.uf; 81.15.Hi; 78.30.Ly.