This study identifies HD-PTP as a central coordinator of the ESCRT pathway for EGFR. Based on these studies, we propose a model whereby the concerted recruitment of CHMP4B and UBPY to HD-PTP and the engagement of UBPY by STAM2 displaces ESCRT-0 from HD-PTP, deubiquitinates EGFR, and releases ESCRT-0 from cargo in favor of ESCRT-III.

The transmembrane protein with epidermal growth factor and two follistatin motifs 2 (TMEFF2) is expressed in prostate and brain and shed from the cell surface in a metalloproteinasedependent fashion. Neither the sheddase(s) responsible for TMEFF2 shedding nor the physiological significance or activity of the soluble TMEFF2 ectodomain (TMEFF2-ECD) has been identified. In the present study we present new evidence that a disintegrin and metalloproteinase-17 (ADAM17) is responsible for phorbol 12-myristate 13-acetate-induced release of TMEFF2-ECD using small interfering RNA to ablate ADAM17 expression or by inhibiting enzymatic activity. A single well shedding assay monitoring the release of alkaline phosphatasetagged TMEFF2-ECD into medium and the generation of 22-and 14-kDa C-terminal fragments in lysates were dependent on ADAM17 activity. A ␥-secretase inhibitor prevented the formation of a 10-kDa fragment in cell lysates, thus establishing TMEFF2 as a novel substrate for regulated intramembrane proteolysis. We assigned proliferation-inducing activity to TMEFF2. Inhibition of TMEFF2 shedding using synthetic metalloproteinase inhibitors or small interfering RNA targeting TMEFF2 expression yielded a statistically significant reduction of cell proliferation in the lymph node-derived prostate cancer cells (LNCaPs) and a human embryonic kidney (HEK293) cell line overexpressing TMEFF2. The TMEFF2-ECD was able to induce ERK1/2 phosphorylation in an epidermal growth factor receptor (or ErbB1)-dependent manner in HEK293 cells. Our data suggest that TMEFF2 contributes to cell proliferation in an ADAM17-dependent autocrine fashion in cells expressing this protein.The transmembrane protein with epidermal growth factor and two follistatin motifs 2 (TMEFF2) 2 gene encodes a modular protein consisting of two follistatin modules, an epidermal growth factor (EGF)-like repeat, and a transmembrane domain connected to a short cytoplasmic tail with a potential G-protein activation motif. TMEFF2 is highly up-regulated in 74% of primary prostate cancer (PCa) and 42% of metastatic lesions from lymph nodes and bone irrespective of hormonal disease status (1). TMEFF2 expression correlates with onset of cellular proliferation after castration in the CWR22 PCa mouse model (2) as well as in the TEN12 xenograft model (3), suggesting that it is not a tumor suppressor (1). However, in a different LNCaP human PCa progression model opposing results were obtained where TMEFF2 expression was highest in low grade disease and down-regulated in aggressive metastatic C4-2 xenografts (4). TMEFF2 expression is absent in androgen-independent PCa cell lines PC3 and DU145 (5). When TMEFF2 expression was re-established in PC3 and DU145 cell lines by stably transfecting these cell lines with TMEFF2 cDNA a 50% decrease in cell proliferation was observed (5), but this finding could not be corroborated by Afar et al. (1). The biological function of TMEFF2 in PCa is unknown, but it has been implicated in cell signaling (6), neuronal cell survival (7), tumor suppr...

TMEFF2 is a type I transmembrane protein with two follistatin (FS) and one EGF‐like domain over‐expressed in prostate cancer; however its biological role in prostate cancer development and progression remains unclear, which may, at least in part, be explained by its proteolytic processing. The extracellular part of TMEFF2 (TMEFF2‐ECD) is cleaved by ADAM17 and the membrane‐retained fragment is further processed by the gamma‐secretase complex. TMEFF2 shedding is increased with cell crowding, a condition associated with the tumour microenvironment, which was mediated by oxidative stress signalling, requiring jun‐kinase (JNK) activation. Moreover, we have identified that TMEFF2 is also a novel substrate for other proteases implicated in prostate cancer, including two ADAMs (ADAM9 and ADAM12) and the type II transmembrane serine proteinases (TTSPs) matriptase‐1 and hepsin. Whereas cleavage by ADAM9 and ADAM12 generates previously identified TMEFF2‐ECD, proteolytic processing by matriptase‐1 and hepsin produced TMEFF2 fragments, composed of TMEFF2‐ECD or FS and/or EGF‐like domains as well as novel membrane retained fragments. Differential TMEFF2 processing from a single transmembrane protein may be a general mechanism to modulate transmembrane protein levels and domains, dependent on the repertoire of ADAMs or TTSPs expressed by the target cell.

As an active learning strategy, problem based learning (PBL) puts the emphasis on students being responsible for their learning (Hmelo-Silver and Barrows 2006). Although it is student-centred, PBL facilitators can help students achieve deep learning through strategies which allow them to check their understanding and engage in critical thinking skills (Wood, 2003; Azer et al,. 2013). However enabling students to engage in critical thinking skills and assessing their learning requires the use of innovative strategies (Azer et al., 2013). This paper describes the development of a learning tool to allow students undertake their own-self assessment. It was developed on the principles of ill-structured problems which encourage the utilization of critical thinking skills (Kek and Huijser, 2011). Thus the aim of the research was to assess whether the tool would allow the students to engage in critical thinking skills such as deep understanding and application of knowledge. Results show students found the tool to be effective for their learning where they were able to apply their knowledge and test understanding. This suggested that the developed tool proved to be useful in engaging students in critical thinking skills and as a means to check student understanding.