A Novel Form of Neuregulin 1 Type III Caused by N-Terminal Processing.

Nrg1 (Neuregulin 1) type III, a susceptible gene of schizophrenia, exhibits a critical role in the central nervous system and is essential at each stage of Schwann's cell development. Nrg1 type III comprises double-pass transmembrane domains, with the N-terminal and C-terminal localizing inside the cells. The N-terminal transmembrane helix partially overlaps with the cysteine-rich domain (CRD). In this study, Nrg1 type III constructs with different tags were transformed into cultured cells to verify whether CRD destroyed the transmembrane helix formation. We took advantage of immunofluorescent and immunoprecipitation assays on whole cells and analyzed the N-terminal distribution. Astonishingly, we found that a novel form of Nrg1 type III, about 10% of Nrg1 type III, omitted the N-terminal transmembrane helix, with the N-terminal positioning outside the membrane. The results indicated that the novel single-pass transmembrane status was a minor form of Nrg1 type III caused by N-terminal processing, while the major form was a double-pass transmembrane status.

The role of Rapsyn in neuromuscular junction and congenital myasthenic syndrome.

Rapsyn, an intracellular scaffolding protein associated with the postsynaptic membranes in the neuromuscular junction (NMJ), is critical for nicotinic acetylcholine receptor clustering and maintenance. Therefore, Rapsyn is essential to the NMJ formation and maintenance, and Rapsyn mutant is one of the reasons causing the pathogenies of congenital myasthenic syndrome (CMS). In addition, there is little research on Rapsyn in the central nervous system (CNS). In this review, the role of Rapsyn in the NMJ formation and the mutation of Rapsyn leading to CMS will be reviewed separately and sequentially. Finally, the potential function of Rapsyn is prospected.

A Glance at the Molecules That Regulate Oligodendrocyte Myelination.

Oligodendrocyte (OL) myelination is a critical process for the neuronal axon function in the central nervous system. After demyelination occurs because of pathophysiology, remyelination makes repairs similar to myelination. Proliferation and differentiation are the two main stages in OL myelination, and most factors commonly play converse roles in these two stages, except for a few factors and signaling pathways, such as OLIG2 (Oligodendrocyte transcription factor 2). Moreover, some OL maturation gene mutations induce hypomyelination or hypermyelination without an obvious function in proliferation and differentiation. Herein, three types of factors regulating myelination are reviewed in sequence.

Extraction, selenylation modification and antitumor activity of the glucan from Castanea mollissima Blume.

The present study aimed to characterize the glucan from C. mollissima Blume fruits and its selenium derivative, then investigate their antitumor activity in vitro. A glucan, designated as CPA, was firstly isolated from the fruits of C. mollissima Blume. Structure analysis indicated that CPA was a linear 1,6-α-D-glucan with the average molecular weight about 2.0 × 103 kDa. The selenylation modification derivative of CPA (sCPA), exhibited a stronger antiproliferative effect on tumor cells than CPA in vitro. CPA and sCPA could induce HeLa cells apoptosis and decrease mitochondrial membrane potential. sCPA could also arrest HeLa cells in S phase, promote reactive oxygen species generation and activate caspase-3 activity in HeLa cells. These results manifest that CPA and sCPA inhibit the proliferation of HeLa cells via different mechanisms, which is meaningful for their potential use as antitumor drugs.

Homolytic C-O cleavage in phosphates and sulfonates.

The C-O homolytic bond dissociation enthalpies(BDEs) were calculated by high-level ab initio including G4, G3B3, G3, CBS-QB3 and a series of density function theory (DFT) methods. It is found that the wB97 method gave the most reliable C-O BDEs and the root-mean-square deviation (RMSD) is 7.6 kJ/mol. Therefore, the C(sp(2))-O BDE predictions and the substituent effects of alkenyl phosphates/sulfonates and aryl phosphates/sulfonates were investigated in detail by using the wB97 method. Interestingly, there exist different substituent effects in α- and ß-substituted alkenyl phosphates/sulfonates. Excellent linear relationships between the C-O BDEs of ß-substituted alkenyl phosphates/sulfonates with substituent constant σp(+) were found. In addition, the NBO analysis further disclosed the essence of the substituent effects on C-O BDEs.