Mastoparan(MAS) and α-latrotoxin(α-LTX) are two kinds of insulinotropic peptides obtained from insect toxins which can interact with islet β-cells and induce insulin secretion. The signal mechanism of these insulin...Mastoparan(MAS) and α-latrotoxin(α-LTX) are two kinds of insulinotropic peptides obtained from insect toxins which can interact with islet β-cells and induce insulin secretion. The signal mechanism of these insulinotropic peptides regulating insulin-releasing attracts notable attention and has been elucidated more and more details. MAS mainly acts on the molecular components of exocytosis at a late stage. Insulin secretion induced by MAS is obviously dependent on GTP,which subsequently activates G-protein located on insulin secretion granules(ISG),or activates the Rho subfamily of small G proteins to evoke exocytosis and sensitize fusion machinery. The MAS stimulated insulin-releasing activity can be augmented by nutrients. However,its effect is not Ca2+ dependent. There are two regulatory pathway triggered by α-LTX: one way is pore formation caused through plasma membrane,another way is the transmembrane signal transduction evoked by cytosolic second messengers. Tetrameri complexs assembled at high concentration of α-LTX toxin or in the presence of extracellular Ca2+,can insert α-LTX into plasma membrane to form Ca2+ permeable channels and trigger Ca2+-dependent secretion. By binding to transmembrane receptors and activating phospholipase C,α-LTX induces the generation of second messenger DAG and IP3. IP3 triggers Ca2+ influx and subsequently activates CaMK pathway,however,DAG also activates PKC pathway to increase insulin release.展开更多
The performance of matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF-MS) is frequently compromised by the high limited of detection, heterogeneous distribution of matrix and analyt...The performance of matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF-MS) is frequently compromised by the high limited of detection, heterogeneous distribution of matrix and analyte deposits and time-consuming drying time during the conventional drop drying procedure. Here, we describe a method based on membrane separation technology to assist in the drying of nanomaterials to rapidly make homogeneous sample spots and to enhance the mass signal. We demonstrate that the sample can be dried evenly in a few seconds and MS signal can be greatly optimized by using membrane separation technology. Enrichment with nanomaterials greatly enhances analyte signal strength while membrane separation method avoids the time-consuming requirements of searching for "sweet spots".展开更多
文摘Mastoparan(MAS) and α-latrotoxin(α-LTX) are two kinds of insulinotropic peptides obtained from insect toxins which can interact with islet β-cells and induce insulin secretion. The signal mechanism of these insulinotropic peptides regulating insulin-releasing attracts notable attention and has been elucidated more and more details. MAS mainly acts on the molecular components of exocytosis at a late stage. Insulin secretion induced by MAS is obviously dependent on GTP,which subsequently activates G-protein located on insulin secretion granules(ISG),or activates the Rho subfamily of small G proteins to evoke exocytosis and sensitize fusion machinery. The MAS stimulated insulin-releasing activity can be augmented by nutrients. However,its effect is not Ca2+ dependent. There are two regulatory pathway triggered by α-LTX: one way is pore formation caused through plasma membrane,another way is the transmembrane signal transduction evoked by cytosolic second messengers. Tetrameri complexs assembled at high concentration of α-LTX toxin or in the presence of extracellular Ca2+,can insert α-LTX into plasma membrane to form Ca2+ permeable channels and trigger Ca2+-dependent secretion. By binding to transmembrane receptors and activating phospholipase C,α-LTX induces the generation of second messenger DAG and IP3. IP3 triggers Ca2+ influx and subsequently activates CaMK pathway,however,DAG also activates PKC pathway to increase insulin release.
基金supported by the National Natural Science Foundation of China (Nos. 21435002, 21621003)
文摘The performance of matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF-MS) is frequently compromised by the high limited of detection, heterogeneous distribution of matrix and analyte deposits and time-consuming drying time during the conventional drop drying procedure. Here, we describe a method based on membrane separation technology to assist in the drying of nanomaterials to rapidly make homogeneous sample spots and to enhance the mass signal. We demonstrate that the sample can be dried evenly in a few seconds and MS signal can be greatly optimized by using membrane separation technology. Enrichment with nanomaterials greatly enhances analyte signal strength while membrane separation method avoids the time-consuming requirements of searching for "sweet spots".
