Evolution of the intracellular transport mechanisms in eukaryotes: ciliates and mammals use the same translocation and nuclear localization signals

In the ciliate E. raikovi, self/non-self recognition phenomena are controlled by cell type-specific, water-borne signal proteins (pheromones) by their binding to target cell-surface receptors. The downstream signal transduction pathway activated by the pheromone-receptor interactions of self type (that promote the vegetative, mitogenic cell growth) involves the phosphorylation of a nuclear protein kinase, designated Er-MAPK1, which is structurally similar to the "intestinal-cell kinase" and "male germ cell-associated kinase" described in mammals. To identify the sequence segments responsible for Er-MAPK1 nuclear localization, mouse fibroblasts were transfected with plasmids containing the reporter gene for the "Green-Fluorescent Protein" (GFP) associated to different fragments of the Er-MAPK1 coding sequence. By expressing GFP-tagged protein constructs in mammalian cells, in the C-terminal domain of Er-MAPK1 it was effectively possible to identify an Arg/Lys-rich motif that is required for the nuclear entry of GFP-fused constructs. These results provide evidence that distant related organisms such as ciliates and mammals use the same molecular language for the nuclear translocation and localization of proteins, thus suggesting that this language arose early in the evolution of the eukaryotic cell

The scaffold protein p140Cap limits ERBB2-mediated breast cancer progression interfering with Rac GTPase-controlled circuitries.

The docking protein p140Cap negatively regulates tumour cell features. Its relevance on breast cancer patient survival, as well as its ability to counteract relevant cancer signalling pathways, are not fully understood. Here we report that in patients with ERBB2-amplified breast cancer, a p140Cap-positive status associates with a significantly lower probability of developing a distant event, and a clear difference in survival. p140Cap dampens ERBB2- positive tumour cell progression, impairing tumour onset and growth in the NeuT mouse model, and counteracting epithelial mesenchymal transition, resulting in decreased metastasis formation. One major mechanism is the ability of p140Cap to interfere with ERBB2- dependent activation of Rac GTPase-controlled circuitries. Our findings point to a specific role of p140Cap in curbing the aggressiveness of ERBB2-amplified breast cancers and suggest that, due to its ability to impinge on specific molecular pathways, p140Cap may represent a predictive biomarker of response to targeted anti-ERBB2 therapies

Palazzo Spada e i pavimenti del Seicento a Roma

Questo libro raccoglie gli interventi di una giornata di studio sui pavimenti del Seicento tenutasi a Palazzo Spada nell’autunno del 2018. Varie vicissitudini, non ultime quelle connesse all’attuale pandemia, hanno dilazionato la pubblicazione dei contributi presentati in quell’occasione; nel frattempo sono comparsi studi e ricerche che hanno portato nuove conoscenze su una componente dell’architettura tanto importante quanto per lungo tempo negletta. In particolare, sono state investigate le caratteristiche cromatiche dei materiali, la loro ricezione e le relative ascendenze letterarie e simboliche. E tuttavia tali contributi hanno solo parzialmente affrontato le pavimentazioni nel concreto contesto delle fabbriche della Roma rinascimentale e seicentesca, in un’ottica unitaria che, del resto, le moderne modalità d’impiego e l’attuale eterogeneità delle funzioni tendono spesso ad offuscare. Crediamo pertanto che la messa a fuoco sui temi dell’ideazione e dell’esecuzione dei pavimenti nella Roma barocca mantenga, anche a tre anni di distanza di quella che fu una riuscita iniziativa di studio, tutta la sua attualità, partendo proprio da palazzo Spada come emblematico caso. Fabbrica tra le più significative, sia per la decorazione originaria che per le trasformazioni intercorse nella prima metà del XVII secolo, il palazzo dei cardinali Capodiferro e Spada conserva tipologie diverse di pavimentazione in cotto, la cui tecnica e princìpi, nonché i partiti decorativi e i documentati esecutori, sono qui ampiamente indagati. Esempio di residenza cardinalizia in cui i motivi geometrici di lunga durata si alternano a nuove invenzioni nel succedersi delle sale di maggiore rappresentatività, Palazzo Spada mostra anche come le tecniche costruttive messe a punto nel Rinascimento conoscano una fase di standardizzazione che contribuirà all’ampia diffusione degli ammattonati anche nell’edilizia medio-alta. Più in generale, viene mostrato qui quanto, soprattutto nel Seicento, la pavimentazione si qualifichi come attivo commento degli spazi interni e ciò in particolare nelle chiese, dove assurge talvolta a vera e propria architettura complanare che dialoga con il suo contesto e dove si confrontano tradizioni di varie provenienze storiche e geografiche. A Roma questa componente passa per le interpretazioni dei maggiori architetti dell’epoca, da Gian Lorenzo Bernini a Francesco Borromini, a Carlo Fontana: almeno due di questi artisti sono assai familiari all’interno del palazzo del cardinal Bernardino Spada e non estranei all’argomento in questione; e, anche in questo caso, la personalità dell’alto prelato è il vero motore dell’incessante fare e disfare dell’edificio

Protein transport into the nucleus: characterization of nuclear localization signals in the protozoan ciliate Euplotes

In E. raikovi, a nuclear protein kinase, designated Er-MAPK1, appears to be phosphorylated in association with the mechanism of signal transduction which promotes cell proliferation through autocrine interactions between cell type-specific signaling protein pheromones and their membrane receptors. This kinase shows significant structural matching to mammalian kinases that are localized in the nucleus of specialized cell types, such as the "Male germ cell-Associated Kinases" and the "Intestinal Cell Kinases". Two Arg/Lys-rich motifs were identified in the Er-MAPK1 C-terminal domain as putative “nuclear localization signals” and their effective function in directing this protein into the nucleus was studied by expressing GFP-tagged protein constructs in mammalian fibroblasts. The results obtained provide evidence that distant related organisms such as ciliates and mammals use the same molecular language for the nuclear translocation and localization of proteins, suggesting that this language arose early in the evolution of the eukaryotic cell

Subcellular targeting of the Euplotes raikovi kinase Er-MAPK1, as revealed by expression in different cell systems

In the ciliate Euplotes raikovi, a 631-amino acid Er-MAPK1 protein kinase was found to localize in nucleoli of the transcriptionally active nucleus (macronucleus) and act as a key component of an autocrine, cell-growth promoting self-signaling mechanism. While its 283-amino acid N-terminal domain includes all the structural specificities of the mitogen-activated protein kinases required for a catalytic function, the 348- amino acid C-terminal domain is structurally unique with undetermined functions. By expressing the two Er-MAPK1 domains tagged with the green fluorescent protein in mammalian fibroblasts, the yeast Schizosaccharomyces pombe and the ciliate Tetrahymena thermophila, evidence was obtained that the C-terminal domain contains all the sequence information responsible for the Er-MAPK1 subcellular localization. However, in fibroblasts and S. pombe this information determined a nucleolar localization of the GFP-tagged C-terminal domain, and a ciliary localization in T. thermophila. In the light of these findings, the Er-MAPK1 localization in E. raikovi was re-examined via immunoreactions and shown to be ciliary besides that nuclear, as is the case for the mammalian intestinal cell kinase with which the Er-MAPK1 N-terminal domain shares a strong sequence identity and a catalytic function