The N-methyl-D-aspartate receptor (NMDAR) in central nerve system is mostly composed of GluN1 and GluN2 subunits. The classical NMDAR has been intensively studied. However, GluN3‑containing NMDAR is much less expressed and have atypical channel properties. Recently, accumulating evidences have revealed two types of GluN3‑containing NMDAR: glutamate-gated GluN1/GluN2/GluN3 NMDAR and glycine-gated GluN1/GluN3 NMDAR. The former may play important roles in regulating synapse maturation and pruning non-used synapses, and its elevated expression at the adult stage may alter synaptic reorganization in some neuropsychiatric disorders. The latter is expressed in the medial habenula and involves in control of aversion. This article reviews the recent progresses on the expression, functional properties of GluN3‑containing atypical NMDARs and the physiological and pathological relevance.
Central Nervous System/metabolism* ; Protein Subunits/metabolism* ; Receptors, N-Methyl-D-Aspartate ; Synapses

Osteoarthritis (OA) is a kind of degenerative disease characterized by hyperosteogeny at the joint margins and articular cartilage degeneration. Mechanical stress can regulate the multiple functions of cells. The integrin as one of the mechanoreceptors on the surface of cells, mainly mediated adhesion between cells and extracellular matrix, which plays an important role in the mechanical signal transmission to regulate the physiological functions of cell. Therefore, it is very important to select proper mechanical stimulation (such as naprapathy) in the early and middle stage of osteoarthritis, which regulate the expression of integrins to affect the function of chondrocytes, repair the damaged chondrocyte and delay the articular cartilage degeneration.
Animals ; Biomechanical Phenomena ; Chondrocytes ; cytology ; metabolism ; pathology ; Gene Expression Regulation ; Humans ; Integrins ; metabolism ; Mechanical Phenomena ; Protein Subunits ; metabolism

Animals ; Cell Respiration ; Electron Transport Complex III ; metabolism ; Humans ; Iron-Sulfur Proteins ; chemistry ; metabolism ; Mitochondria ; metabolism ; Peptide Fragments ; chemistry ; metabolism ; Protein Multimerization ; Protein Structure, Quaternary ; Protein Subunits ; chemistry

OBJECTIVE: To investigate the expression of adaptin-2(AP-2) in mice cochlea and to discuss the probable role in the endocytosis of hair cells. METHOD: Laser scanning confocal microscopy and immune-fluroscence histochemistry were performed in this study. RESULT: In mature mice cochlea, the immunoreactivity for AP-2 was found in the inner hair cells cytoplasm. This protein mainly expressed in the hair cells basal part and nearby the ribbon synapse. CONCLUSION AP-2 protein mainly expressed in the hair cells synaptic activity zone , which suggested that AP-2 could play an important role in the synaptic vesicle endocytosis. This finding built the foundation for the further research involved in the physiological and pathological role of AP-2.
Adaptor Protein Complex alpha Subunits ; metabolism ; Animals ; Cochlea ; Hair Cells, Auditory ; Hair Cells, Auditory, Inner ; metabolism ; Mice ; Microscopy, Confocal ; Synapses

Inhibin, which is important for normal gonadal function, acts on the pituitary gonadotropins to suppress folliclestimulating hormone (FSH) secretion. The level and cellular localization of the inhibin isotypes, alpha, beta(A) and beta(B), in the testis of mice were examined during postnatal development in order to determine if inhibin expression is related to testicular maturation. Mouse testes were sampled on postnatal days (PNDs) 1, 3, 6, 18, 48 and 120, and analyzed by Western blotting and immunofluorescence. Western blot analysis showed very low levels of inhibin alpha, beta(A) and beta(B) expression in the testes at days 1 to 6 after birth. The levels then increased gradually from PND 18 to 48-120, and there were significant peaks at PND 48. Inhibin alpha, beta(A) and beta(B) were detected in testicular cells during postnatal development using immunohistochemistry. The immunoreactivity of inhibin alpha was rarely observed in testicular cells during PND 1 to 6, or in the cytoplasmic process of Sertoli cells surrounding the germ cells and interstitial cells during PND 18 to 120. Inhibin beta(A) and beta(B) immunoreactivity was rarely observed in the testis from PND 1 to 6. On the other hand, it was observed in some spermatogonial cells, as well as in the interstitial space between PND 48 and PND 120. We conclude that the expression of inhibin isotypes increases progressively in the testis of mice with increasing postnatal age, suggesting that inhibin is associated with a negative feedback signal for FSH in testicular maturation.
Aging/*physiology ; Animals ; Gene Expression Regulation/*physiology ; Inhibin-beta Subunits/genetics/*metabolism ; Inhibins/genetics/*metabolism ; Male ; Mice ; Mice, Inbred ICR ; Protein Isoforms/metabolism ; Protein Transport/*physiology ; Testis/*metabolism

Proto-Oncogene Proteins c-akt ; TOR Serine-Threonine Kinases ; GTP-Binding Protein alpha Subunits, Gi-Go/metabolism*

By now, the digestive stability experiments provided by most authoritative organizations are in vitro tests. Evaluating the protein digestive stability with in vivo models should be more objective. The present study aimed to verify the in vivo digestibility of soybean β-conglycinin β-subunit in Wuzhishan (WZS) minipigs. Three minipigs were surgically fitted with O-stomach and T-ileum cannulae and fed with soybean meals. According to SDS-PAGE, the 50 kD fraction of soybean β-conglycinin β-subunit persisted in the gastric fluid until 6 h after feeding, which was detected at 3 h and clearly visible at 4-6 h in the intestinal fluid. Western blot with anti-β-conglycinin β-subunit McAb confirmed it.
Animals ; Antigens, Plant ; chemistry ; metabolism ; Digestion ; physiology ; Globulins ; chemistry ; metabolism ; Male ; Protein Subunits ; chemistry ; metabolism ; Seed Storage Proteins ; chemistry ; metabolism ; Soybean Proteins ; chemistry ; metabolism ; Swine ; Swine, Miniature ; physiology

The human Shwachman-Diamond syndrome (SDS) is an autosomal recessive disease caused by mutations in a highly conserved ribosome assembly factor SBDS. The functional role of SBDS is to cooperate with another assembly factor, elongation factor 1-like (Efl1), to promote the release of eukaryotic initiation factor 6 (eIF6) from the late-stage cytoplasmic 60S precursors. In the present work, we characterized, both biochemically and structurally, the interaction between the 60S subunit and SBDS protein (Sdo1p) from yeast. Our data show that Sdo1p interacts tightly with the mature 60S subunit in vitro through its domain I and II, and is capable of bridging two 60S subunits to form a stable 2:2 dimer. Structural analysis indicates that Sdo1p bind to the ribosomal P-site, in the proximity of uL16 and uL5, and with direct contact to H69 and H38. The dynamic nature of Sdo1p on the 60S subunit, together with its strategic binding position, suggests a surveillance role of Sdo1p in monitoring the conformational maturation of the ribosomal P-site. Altogether, our data support a conformational signal-relay cascade during late-stage 60S maturation, involving uL16, Sdo1p, and Efl1p, which interrogates the functional P-site to control the departure of the anti-association factor eIF6.
Crystallography, X-Ray ; GTP Phosphohydrolases ; chemistry ; metabolism ; Humans ; Protein Domains ; Ribosome Subunits, Large, Eukaryotic ; chemistry ; metabolism ; Saccharomyces cerevisiae ; chemistry ; metabolism ; Saccharomyces cerevisiae Proteins ; chemistry ; metabolism

OBJECTIVETo develop toxin targeting vascular endothelial growth factor receptor II (VEGF-II/KDR) fused with a KDR-binling peptide screened from peptide library.

METHODSBy affinity to KDR molecular which expressed specifically by new born vascular endothelial cell, peptides to KDR were screened from C7 peptide library by phage display. Among them, a peptide binding to KDR with high affinity termed as P5 was selected and fused to the N-terminal of Shiga toxin subunit A (StxA). The protein (P5-StxA) was expressed in E. coli.

RESULTSELISA and Western blot were applied to characterize the binding interaction between the fusion protein, P5-StxA and KDR. Cytotoxicity assay showed that P5-StxA maintained similar toxicity to cell as StxA. In the model of angiogenesis, P5-StxA inhibited selectively VEGF-induced growth of preexisting vessels of the chick chorioallantoic membrane.

CONCLUSIONThese studies demonstrate the small peptide, P5, maybe be used as carrier of toxin targeting to KDR.

Blotting, Western ; Enzyme-Linked Immunosorbent Assay ; Humans ; Peptide Library ; Protein Subunits ; Recombinant Fusion Proteins ; metabolism ; Shiga Toxin ; metabolism ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism

Large-conductance Ca²⁺-activated K⁺ channels (BK channels) constitute an key physiological link between cellular Ca²⁺ signaling and electrical signaling at the plasma membrane. Thus these channels are critical to the control of action potential firing and neurotransmitter release in several types of neurons, as well as the dynamic control of smooth muscle tone in resistance arteries, airway, and bladder. Recent advances in our understanding of K⁺ channel structure and function have led to new insight toward the molecular mechanisms of opening and closing (gating) of these channels. Here we will focus on mechanisms of BK channel gating by Ca²⁺, transmembrane voltage, and auxiliary subunit proteins.
Animals ; Calcium Signaling ; Cytoplasm ; metabolism ; Electric Conductivity ; Electrophysiological Phenomena ; Humans ; Ion Channel Gating ; Large-Conductance Calcium-Activated Potassium Channels ; chemistry ; metabolism ; Protein Subunits ; chemistry ; metabolism