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Summary AXL is activated by its ligand GAS6 and is expressed in triple-negative breast cancer cells. In the current study, we report AXL expression in HER2-positive (HER2 + ) breast cancers where it correlates with poor patient survival. Using murine models of HER2 + breast cancer, Axl, but not its ligand Gas6, was found to be essential for metastasis. We determined that AXL is required for intravasation, extravasation, and growth at the metastatic site. We found that AXL is expressed in HER2 + cancers displaying epithelial-to-mesenchymal transition (EMT) signatures where it contributes to sustain EMT. Interfering with AXL in a patient-derived xenograft (PDX) impaired transforming growth factor β (TGF-β)-induced cell invasion. Last, pharmacological inhibition of AXL specifically decreased the metastatic burden of mice developing HER2 + breast cancer. Our data identify AXL as a potential anti-metastatic co-therapeutic target for the treatment of HER2 + breast cancers. [ABSTRACT FROM AUTHOR]

Cancer cells exploit the epithelial-to-mesenchymal transition (EMT) program to become metastatic. Cytoskeletal regulators are required in mesenchymal cells where they promote EMT and EMT-induced migration. In a search for regulators of metastasis, we conducted shRNA screens targeting the microtubule plus-end tracking proteins (+TIPs). We show that the +TIP ACF7 is essential both for the maintenance of the EMT program and to promote migration. We find that the E3 ubiquitin ligase HectD1 promotes ACF7-proteasome-mediated degradation. Depletion of HectD1 stabilized ACF7, and this enhanced EMT and migration. Decreased HectD1 expression increased metastases in mouse models and conferred increased resistance to the cytotoxic drug cisplatin. A retrospective analysis of biopsies from breast cancer patients also reveals a correlation between higher ACF7 or lower HectD1 expression with poor clinical outcomes. Together, these results suggest that the control of ACF7 levels by HectD1 modulates EMT and the efficiency of metastasis. [ABSTRACT FROM AUTHOR]

Distinct functions mediated by members of the monopolar spindle-one-binder (MOB) family of proteins remain elusive beyond the evolutionarily conserved and well-established roles of MOB1 (MOB1A/B) in regulating tissue homeostasis within the Hippo pathway. Since MOB proteins are adaptors, understanding how they engage in protein–protein interactions and help assemble complexes is essential to define the full scope of their biological functions. To address this, we undertook a proximity-dependent biotin identification approach to define the interactomes of all seven human MOB proteins in HeLa and human embryonic kidney 293 cell lines. We uncovered >200 interactions, of which at least 70% are unreported on BioGrid. The generated dataset reliably recalled the bona fide interactors of the well-studied MOBs. We further defined the common and differential interactome between different MOBs on a subfamily and an individual level. We discovered a unique association between MOB3C and 7 of 10 protein subunits of the RNase P complex, an endonuclease that catalyzes tRNA 50 maturation. As a proof of principle for the robustness of the generated dataset, we validated the specific interaction of MOB3C with catalytically active RNase P by using affinity purification–mass spectrometry and pre-tRNA cleavage assays of MOB3C pulldowns. In summary, our data provide novel insights into the biology of MOB proteins and reveal the first interactors of MOB3C, components of the RNase P complex, and hence an exciting nexus with RNA biology. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of (bromoethynyl)benzene with κ2-acetylacetonatobis(trimethylphosphine)rhodium(I), [Rh(acac)(PMe3)2] 1, was followed by in situ 1H and 31P NMR spectroscopy. The kinetic product is that of cis-oxidative addition of the C–Br bond to Rh, and this species rearranges to the thermodynamically more stable trans-oxidative addition product trans-[Rh(acac)(Br)(CCPh)(PMe3)2] 3. The structures of both 1 and 3 have been determined by single-crystal X-ray diffraction. [Copyright &y& Elsevier]

Abstract: NMR study of the reactivity of multifunctional ligand cis,cis-C6H9(NHCH2C6H4-o-PPh2)3 (1) with GaMe3 and Zr(NMe2)4 was carried out, yielding [cis,cis-(κN-NHCH2C6H4-o-PPh2)(κN-NCH2C6H4-o-PPh2)2C6H9]GaMe (2) and [cis,cis-(NCH2C6H4-o-PPh2)3C6H9]Ga2Me3 (3), and [cis,cis-(NCH2C6H4-o-PPh2)3C6H9]Zr(NMe2) (4), respectively. The spectral properties of 2 and 3 are very similar to that observed for the equivalent aluminum species already reported, but form at a much slower rate which allows for the observation of a GaMe3⋅1 adduct. Species 4 undergoes coordination/displacement of one of the phosphine arms, which was observed using both NMR spectroscopy and DFT analyses. [Copyright &y& Elsevier]