Requirement for the N-Terminal Coiled-Coil Domain for Expression and Function, but not Subunit Interaction of, the ADPR-Activated TRPM2 Channel

Transient receptor potential melastatin 2 (TRPM2) proteins form multiple-subunit complexes, most likely homotetramers, which operate as Ca2+-permeable, nonselective cation channels activated by intracellular ADP-ribose (ADPR) and oxidative stress. Each TRPM2 channel subunit is predicted to contain two coiled-coil (CC) domains, one in the N-terminus and the other in the C-terminus. Our recent study has shown that the C-terminal CC domain plays an important, but not exclusive, role in the TRPM2 channel assembly. This study aimed to examine the potential role of the N-terminal CC domain. Domain deletion dramatically reduced protein expression and abolished ADPR-evoked currents but did not alter the subunit interaction. Deletion of both CC domains strongly attenuated the subunit interaction, confirming that the C-terminal CC domain is critical in the subunit interaction. Glutamine substitutions into individual hydrophobic residues at positions a and d in the heptad repeats to disrupt the CC formation had no effect on protein expression, subunit interaction, or ADPR-evoked currents. Mutation of Ile658 to glutamine, which did not perturb the CC formation, decreased ADPR-evoked currents without affecting protein expression, subunit interaction, or membrane trafficking. These results collectively suggest the requirement for the N-terminal CC domain for protein expression and function, but not subunit interaction, of the TRPM2 channel

Characterization of calcium deposition induced by Synechocystis sp PCC6803 in BG11 culture medium

Calcium carbonate (CaCO3) crystals in their preferred orientation were obtained in BG11 culture media inoculated with Synechocystis sp. PCC6803 (inoculated BG11). In this study, the features of calcium carbonate deposition were investigated. Inoculated BG11 in different calcium ion concentrations was used for the experimental group, while the BG11 culture medium was used for the control group. The surface morphologies of the calcium carbonate deposits in the experimental and control groups were determined by scanning and transmission electron microscopy. The deposits were analyzed by electronic probe micro-analysis, Fourier transform infrared spectrum, X-ray diffraction, thermal gravimetric analysis and differential scanning calorimetry. The results show that the surfaces of the crystals in the experimental group were hexahedral in a scaly pattern. The particle sizes were micrometer-sized and larger than those in the control group. The deposits of the control group contained calcium (Ca), carbon (C), oxygen (O), phosphorus (P), iron (Fe), copper (Cu), zinc (Zn), and other elements. The deposits in the experimental group contained Ca, C, and O only. The deposits of both groups contained calcite. The thermal decomposition temperature of the deposits in the control group was lower than those in the experimental group. It showed that the CaCO3 deposits of the experimental group had higher thermal stability than those of the control group. This may be due to the secondary metabolites produced by the algae cells, which affect the carbonate crystal structure and result in a close-packed structure. The algae cells that remained after thermal weight loss were heavier in higher calcium concentrations in BG11 culture media. There may be more calcium-containing crystals inside and outside of these cells. These results shall be beneficial for understanding the formation mechanism of carbonate minerals.Calcium carbonate (CaCO3) crystals in their preferred orientation were obtained in BG11 culture media inoculated with Synechocystis sp. PCC6803 (inoculated BG11). In this study, the features of calcium carbonate deposition were investigated. Inoculated BG11 in different calcium ion concentrations was used for the experimental group, while the BG11 culture medium was used for the control group. The surface morphologies of the calcium carbonate deposits in the experimental and control groups were determined by scanning and transmission electron microscopy. The deposits were analyzed by electronic probe micro-analysis, Fourier transform infrared spectrum, X-ray diffraction, thermal gravimetric analysis and differential scanning calorimetry. The results show that the surfaces of the crystals in the experimental group were hexahedral in a scaly pattern. The particle sizes were micrometer-sized and larger than those in the control group. The deposits of the control group contained calcium (Ca), carbon (C), oxygen (O), phosphorus (P), iron (Fe), copper (Cu), zinc (Zn), and other elements. The deposits in the experimental group contained Ca, C, and O only. The deposits of both groups contained calcite. The thermal decomposition temperature of the deposits in the control group was lower than those in the experimental group. It showed that the CaCO3 deposits of the experimental group had higher thermal stability than those of the control group. This may be due to the secondary metabolites produced by the algae cells, which affect the carbonate crystal structure and result in a close-packed structure. The algae cells that remained after thermal weight loss were heavier in higher calcium concentrations in BG11 culture media. There may be more calcium-containing crystals inside and outside of these cells. These results shall be beneficial for understanding the formation mechanism of carbonate minerals

Cigarette Smoking and Cognitive Function in Chinese Male Schizophrenia: A Case-Control study

Schizophrenic patients have higher smoking rates than the general population. Studies show that smoking may be a form of self-medication in an attempt to alleviate cognitive deficits in schizophrenic patients of European background. This study examined the relationships between smoking and cognitive deficits in Chinese schizophrenic patients, which have previously received little systemic study. We recruited 580 male chronic patients meeting DSM-IV criteria for schizophrenia and 175 male control subjects who were matched on age and education. The subjects completed a detailed cigarette smoking questionnaire, the Fagerstrom Test for Nicotine Dependence (FTND), and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Patients also were rated on the Positive and Negative Symptom Scale (PANSS), the Simpson and Angus Extrapyramidal Symptom Rating Scale (SAES), and the Abnormal Involuntary Movement Scale (AIMS). All five RBANS subscales except for the Visuospatial/Constructional index showed significantly lower cognitive performance for schizophrenics than normal controls. The schizophrenic smokers scored lower than the schizophrenic non-smokers on the RBANS total score and the Visuospatial/Constructional and Immediate Memory indices. Similarly, the control smokers scored lower than the control non-smokers on the RBANS total score and the Immediate Memory index . Also, the schizophrenic smokers consistently performed the poorest on the cognitive domains of the RBANS. Among the schizophrenic patients, smokers displayed significantly fewer negative symptoms than non-smokers. Using multivariate regression analysis the following variables were independently associated with the RBANS total score: years of education, PANSS negative symptom score, age at schizophrenia onset, and number of hospitalizations. Our results show that smoking is associated with significant cognitive impairment in both schizophrenic patients and normal controls, but the smokers with schizophrenia had a reduced level of negative symptoms, suggesting that the benefits of smoking for those with schizophrenia may be limited to certain aspects of a given clinical phenotype

The alpha-kinase family: an exceptional branch on the protein kinase tree

The alpha-kinase family represents a class of atypical protein kinases that display little sequence similarity to conventional protein kinases. Early studies on myosin heavy chain kinases in Dictyostelium discoideum revealed their unusual propensity to phosphorylate serine and threonine residues in the context of an alpha-helix. Although recent studies show that some members of this family can also phosphorylate residues in non-helical regions, the name alpha-kinase has remained. During evolution, the alpha-kinase domains combined with many different functional subdomains such as von Willebrand factor-like motifs (vWKa) and even cation channels (TRPM6 and TRPM7). As a result, these kinases are implicated in a large variety of cellular processes such as protein translation, Mg2+ homeostasis, intracellular transport, cell migration, adhesion, and proliferation. Here, we review the current state of knowledge on different members of this kinase family and discuss the potential use of alpha-kinases as drug targets in diseases such as cancer

Inactivation of TRPM2 channels by extracellular divalent copper

Cu2+ is an essential metal ion that plays a critical role in the regulation of a number of ion channels and receptors in addition to acting as a cofactor in a variety of enzymes. Here, we showed that human melastatin transient receptor potential 2 (hTRPM2) channel is sensitive to inhibition by extracellular Cu2+. Cu2 + at concentrations as low as 3 μM inhibited the hTRPM2 channel completely and irreversibly upon washing or using Cu2+ chelators, suggesting channel inactivation. The Cu2+-induced inactivation was similar when the channels conducted inward or outward currents, indicating the permeating ions had little effect on Cu2+-induced inactivation. Furthermore, Cu2+ had no effect on singe channel conductance. Alanine substitution by site-directed mutagenesis of His995 in the pore-forming region strongly attenuated Cu2+-induced channel inactivation, and mutation of several other pore residues to alanine altered the kinetics of channel inactivation by Cu2+. In addition, while introduction of the P1018L mutation is known to result in channel inactivation, exposure to Cu2+ accelerated the inactivation of this mutant channel. In contrast with the hTRPM2, the mouse TRPM2 (mTRPM2) channel, which contains glutamine at the position equivalent to His995, was insensitive to Cu2+. Replacement of His995 with glutamine in the hTRPM2 conferred loss of Cu2+-induced channel inactivation. Taken together, these results suggest that Cu2+ inactivates the hTRPM2 channel by interacting with the outer pore region. Our results also indicate that the amino acid residue difference in this region gives rise to species-dependent effect by Cu2+ on the human and mouse TRPM2 channels

Management experiences of primary angiosarcoma of breast: a retrospective study from single institute in the People’s Republic of China

Qun-Chao Hu,1–3,* Xin Mei,1,2,* Yan Feng,1,2 Jin-Li Ma,1,2 Zhao-Zhi Yang,1,2 Zhi-Min Shao,2,4 Xiao-Li Yu,1,2 Xiao-Mao Guo1,2 1Department of Radiation Oncology, Fudan University Shanghai Cancer Center, 2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 3Department of Radiation Oncology, Suzhou Municipal Hospital, Suzhou, 4Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Primary angiosarcoma of breast (PAOB) is a rare and highly aggressive malignancy. There is no general agreement on optimal treatments or prognostic factors for this orphan disease. The objective of this study was to investigate the clinicopathologic features and management experiences of PAOB.Methods: We performed a retrospective review of medical and pathologic records of 17 consecutive patients diagnosed with PAOB between January 2000 and February 2014 at FuDan University Shanghai Cancer Center. We evaluated the clinical characteristics, multimodality treatments, and associated clinical outcomes.Results: A total of 16 patients were included in this retrospective study (median age at PAOB presentation 33.5 years, range: 19–56 years). Palpable tumor with or without breast skin ecchymosis presented as the most common initial symptom. All patients underwent surgery with curative intent. Median disease-free survival and overall survival (OS) were 9 months and 13.6 months, respectively. One-year and 3-year disease-free survival rates were 43.8% and 6.3%, with OS rates of 93.8% and 78.1%, respectively. High histologic grade indicated poorer OS by univariate analysis (P=0.01). However, neither adjuvant chemotherapy nor radiotherapy contributed to clinical outcomes in our series.Conclusion: PAOB is considered as an infrequent breast neoplasm with aggressive characteristics. Histologic grade and early metastasis (within 12 months after diagnosis) are associated with poor prognosis. Regardless of grade, additional benefit was not observed with adjuvant therapy. Keywords: primary angiosarcoma, breast neoplasm, histologic grade, adjuvant therap