Comparative Nucleotide-Dependent Interactome Analysis Reveals Shared and Differential Properties of KRas4a and KRas4b

The KRAS gene encodes two isoforms, KRas4a and KRas4b. Differences in the signaling functions of the two KRas proteins are poorly understood. Here we report the comparative and nucleotide-dependent interactomes of KRas4a and KRas4b. Many previously unknown interacting proteins were identified, with some interacting with both isoforms while others prefer only one. For example, v-ATPase a2 and eIF2Bδ interact with only KRas4b. Consistent with the v-ATPase interaction, KRas4b has a significant lysosomal localization. Comparing WT and constitutively active G12D mutant KRas, we examined differences in the effector proteins of the KRas4a and KRas4b. Interestingly, KRas4a binds RAF1 stronger than KRas4b. Correspondingly, KRas4a can better promote ERK phosphorylation and anchorage-independent growth than KRas4b. The interactome data represent a useful resource to understand the differences between KRas4a and KRas4b and to discover new function or regulation for them. A similar proteomic approach would be useful for studying numerous other small GTPases

Comparative Nucleotide-Dependent Interactome Analysis Reveals Shared and Differential Properties of KRas4a and KRas4b

The KRAS gene encodes two isoforms, KRas4a and KRas4b. Differences in the signaling functions of the two KRas proteins are poorly understood. Here we report the comparative and nucleotide-dependent interactomes of KRas4a and KRas4b. Many previously unknown interacting proteins were identified, with some interacting with both isoforms while others prefer only one. For example, v-ATPase a2 and eIF2Bδ interact with only KRas4b. Consistent with the v-ATPase interaction, KRas4b has a significant lysosomal localization. Comparing WT and constitutively active G12D mutant KRas, we examined differences in the effector proteins of the KRas4a and KRas4b. Interestingly, KRas4a binds RAF1 stronger than KRas4b. Correspondingly, KRas4a can better promote ERK phosphorylation and anchorage-independent growth than KRas4b. The interactome data represent a useful resource to understand the differences between KRas4a and KRas4b and to discover new function or regulation for them. A similar proteomic approach would be useful for studying numerous other small GTPases

Giant enhancement of higher-order harmonics of an optical-tweezer phonon laser

Phonon lasers, as mechanical analogues of optical lasers, are unique tools for not only fundamental studies of phononics but also diverse applications such as acoustic imaging and force sensing. Very recently, by levitating a micro-size sphere in an optical tweezer, higher-order mechanical harmonics were observed in the phonon-lasing regime, as the first step towards nonlinear levitated optomechanics [Nat. Phys. 19, 414 (2023)]. However, both the lasing strengths and the quality factors of the observed harmonics are typically very low, thus severely hindering their applications. Here we show that, by applying a simple but powerful electronic control to such a levitated micro-sphere, three orders of magnitude enhancement are achievable in the brightness of the phonon lasers, including both the fundamental mode and all its higher-order harmonics. Also, giant improvements of their linewidth and frequency stability are realized in such an electro-optomechanical system, together with further improved higher-order phonon coherence. These results, as a significant step forward for enhancing and controlling micro-object phonon lasers, can be readily used for a wide range of applications involving nonlinear phonon lasers, such as acoustic frequency comb, ultra-sound sensing, atmospherical monitoring, and even bio-medical diagnosis of levitated micro-size objects

Synthesis, Aggregation-Induced Emission, and Liquid Crystalline Structure of Tetraphenylethylene<b>–</b>Surfactant Complex via Ionic Self-Assembly

A novel tetraphenylethylene material with liquid crystalline (LC) helical structure and aggregation-induced emission (AIE) property was prepared by ionic self-assembly (ISA). The AIE activity, phase behavior, self-assembly structure, and molecular packing behavior of the complex were then elucidated via a combination of different experimental techniques such as UV–vis absorption spectra, photoluminescence spectra, differential scanning calorimetry, polarized optical microscopy, one- and two-dimensional X-ray diffraction, and Fourier transform infrared spectroscopy. The experimental results reveal that the ISA complex possesses high-efficiency luminescent property with quantum yield as high as 46% in solid state. Meanwhile, the complex could self-assemble into different interesting structures which are sensitive to peripheral chain motions. During heating, the complex takes a low-ordered helical supramolecular structure at ambient temperature and then forms another LC phase with high-ordered helical molecular stacking. These ordered hierarchical structures, in combination with the liquid crystallinity and excellent AIE property of the ISA complex, make it a promising material for fabrication of luminescent devices

Dasatinib enhances the phosphorylation of MEK/ERK cascades.

<p>HL60 cells were treated with dasatinib (10 µM) for the indicated times. The expressions of phosphorylated MEK, ERK, p38, JNK and AKT as well as their total proteins were analyzed by Western blotting. All the experiments were repeated three times and the data show the representative results.</p

Dasatinib induces differentiation of NB4 cells.

<p>NB4 cells were treated with different concentrations of dasatinib for the indicated times. (A) The percentages of CD11b expression cells were determined as described. Data presented are the mean ± SD of three independent experiments. *** P<.001, ** P<.01 versus vehicle treated cells. (B) Cell cycle proportion was analyzed as described. Data presented are the mean ± SD of three independent experiments. *** P<.001, ** P<.01, */# P<.05 versus vehicle treated cells. (C) HL60 cells were treated with dasatinib (10 µM) for 72 h and NB4 cells were treated with dasatinib (5 µM) for 48 h. Cells were collected and cytospined onto slides, then stained with Wright–Giemsa stain. Stained cells were observed under microscope (×40). The data are representative of three independent experiments.</p

Dasatinib-induced AML differentiation requires MEK/ERK-dependent activation of STAT1.

<p>HL60 cells were treated with dasatinib (10 µM) in the presence of PD98059 (20 µM) for 72 h, and NB4 cells were treated with dasatinib (5 µM) in the presence of PD98059 (10 µM) for 48 h. HL60 and NB4 cells were pretreated with PD98059 for 1 h, and then incubated with dasatinb. (A) The percentages of CD11b expression cells were determined as described. Data presented are the mean ± SD of three independent experiments. (B) Cell cycle proportion was analyzed as described. Data presented are the mean ± SD of three independent experiments. *** P<.001, * P<.05. (C) and (D) The expression of p-MEK, p-ERK, p-STAT1(Y701) and p-STAT1(S727) as well as their total proteins in HL60 and NB4 cells were analyzed by Western blotting. The experiments were repeated three times and the data show the representative results.</p

Solubility of Na₂CO₃ and NaHCO₃ in Aqueous Sodium Sulfate Solutions and Its Application to Separating Na₂CO₃ and Na₂SO₄ Salt Mixtures

To separate a salt mixture (mainly consisting of Na₂CO₃ and Na₂SO₄) which is formed from the 4,4′-diaminostilbene-2,2′-disulfonic acid wastewater treatment, the solubility data of Na₂CO₃ and NaHCO₃ in Na₂SO₄–water solvent mixtures were measured using a dynamic method over the 275–335 K temperature range. The solute-free mass fraction of Na₂SO₄ in the solvent mixtures extended from 0 to 0.25. The solubility of Na₂CO₃ and NaHCO₃ in Na₂SO₄–water solvent mixtures decreased with addition of Na₂SO₄. With rising temperature, the solubility of NaHCO₃ increased while the solubility of Na₂CO₃ increased at first and then decreased after transition points. The experimental data were correlated with the electrolyte nonrandom two-liquid model. The root-mean-square deviations of solubility temperature varied from 0.35 to 1.50 K. Based on the solubility data of this work, a new strategy for separating the Na₂CO₃ and Na₂SO₄ mixture was proposed theoretically

Silencing of STAT1 expression by shRNA inhibits dasatinib-induced differentiation of HL60 cells.

<p>HL60 cells transduced with empty vector, Non-target shRNA or STAT1 shRNA (shSTAT1-1 and shSTAT1-2) were treated with dasatinib (10 µM) for 72 h. (A) STAT1 expression was detected by Western blotting. Band intensities were quantified using Quantity One 4.4.0 software (Bio-Rad) and then normalized to the amount of GAPDH in each sample. All samples were compared with the signal detected in Non-target shRNA transduced cells. The data are representative of three independent experiments. (B) NBT reduction assay was performed as described. The percentage of NBT-positive cells was calculated by counting at least 200 cells under a light microscope. Data presented are the mean ± SD of three independent experiments. *** P<.001 (C) CD11b expression was measured by flow cytometer. Data presented are the mean ± SD of three independent experiments. ** P<.01, * P<.05 (D) Cells were collected onto slides by cytospin, stained by Wright–Giemsa stain and observed under microscope. Original magnification, ×40. The data are representative of three independent experiments.</p

Dasatinib exhibits dose- and time-dependent effect on inducing differentiation of HL60 cells.

<p>HL60 cells were treated with dasatinib for the indicated times. Aliquots of the cultures were withdrawn at each time point and subjected to manual counting, following trypan blue staining for determination of (A) the total number of viable cells and (B) the percentage of viable cells. Data presented are the mean ± SD of cell numbers from triplicate wells. The experiments were repeated twice. *** P<.001 versus vehicle treated cells. (C) and (E) The percentages of CD11b expression cells were analyzed as described. Data presented are the mean ± SD of three independent experiments. *** P<.001 and * P<.05 versus vehicle treated cells. (D) and (F) Cell cycle proportion was analyzed by flow cytometer, following propidium iodide staining. Data presented are the mean ± SD of three independent experiments. *** P<.001, **/## P<.01, */# P<.05 versus vehicle treated cells. (G) Cell extracts were subjected to Western blotting analysis with specific antibodies. The results are representative of three independent experiments.</p