The phenomenon of phase separation of intracellular biological macromolecules is an emerging research field that has received great attention in recent years. As an aggregation and compartment mechanism of cell biochemical reactions, it widely exists in nature and participates in important physiological processes such as gene transcription and regulation, as well as influences organism's response to external stimuli. Disequilibrium of phase separation may lead to the occurrence of some major diseases. Researchers in cross-cutting fields are trying to examine dementia and other related diseases from a new perspective of phase separation, exploring its molecular mechanism and the potential possibility of intervention and treatment. This review intends to introduce the latest research progress in this field, summarize the major research directions, biochemical basis, its relationship with disease occurrence, and giving a future perspective of key problems to focus on.
Animals ; Chemistry Techniques, Analytical ; trends ; Cytoplasm ; chemistry ; metabolism ; Humans ; Macromolecular Substances ; isolation & purification ; Research ; trends

OBJECTIVETo investigate the expression of beta-catenin and its significance in colorectal neoplasms.

METHODSTissue specimens of normal colorectal mucosa, mucosa adjacent to carcinoma, colorectal adenoma and adenocarcinoma were examined for beta-catenin with immunohistochemistry.

RESULTSBeta-catenin was mainly expressed in the cytomembrane of normal mucosa and mucosa adjacent to cancer (the positive rates were 94.6% and 86.5%, respectively) and also in the cytoplasm (the positive rates were 38.7% and 55.0%, respectively), while its expression was negative in the cell nucleus. In adenoma and adenocarcinoma, beta-catenin was mainly expressed in the cytoplasm (the positive rates were 85.1%,and 93.7%, respectively) and partially in the cell nucleus (the positive rates were 12.8% and 23.4%, respectively). Compared with normal mucosa and mucosa adjacent to cancer, the expression of beta- catenin in the cytomembrane of adenoma and adenocarcinoma was significantly lower (P<0.05), while its expression in the cytoplasm and cell nucleus of adenoma and adenocarcinoma was significantly higher (P<0.05). The positive rates of cytoplasm in highly-and moderately differentiated adenocarcinoma were significantly higher than that in poorly-differentiated adenocarcinoma (the positive rates were 100%, 95.5% and 68.8%, respectively). Beta-catenin expression rate in cytoplasm was correlated with Dukes'stages of adenocarcinoma, which was significantly lower in stage A than in stage B/C.

CONCLUSIONThe expression of beta-catenin is significantly correlated with differentiation and Dukes'stages of colorectal carcinoma and it can be used as an indicator for the prognosis of colorectal carcinoma.

Adenocarcinoma ; chemistry ; pathology ; Adenoma ; chemistry ; pathology ; Colorectal Neoplasms ; chemistry ; pathology ; Cytoplasm ; chemistry ; Cytoskeletal Proteins ; analysis ; Humans ; Immunohistochemistry ; Prognosis ; Trans-Activators ; analysis ; beta Catenin

Cytochrome P450 3A4 (CYP3A4), is the dominant human liver hemoprotein enzyme localized in the endoplasmic reticulum (ER), and is responsible for the metabolism of more than 50% of clinically relevant drugs. While we were studying CYP3A4 expression and activity in human liver, we found that anti-CYP3A4 antibody cross-reacted with a lower band in liver cytoplasmic fraction. We assessed the activities of CYP3A4 and its truncated form in the microsomal and cytoplasmic fraction, respectively. In the cytoplasmic fraction, truncated CYP3A4 showed catalytic activity when reconstituted with NADPH-cytochrome P-450 reductase and cytochrome b5. In order to determine which site was deleted in the truncated form in vitro, we transfected cells with N-terminal tagged or C-terminal tagged human CYP3A4 cDNA. The truncated CYP3A4 is the N-terminal deleted form and was present in the soluble cytoplasmic fraction. Our result shows, for the first time, that N-terminal truncated, catalytically active CYP3A4 is present principally in the cytoplasm of human liver cells.
Blotting, Western ; Catalysis ; Cell Line ; Cytochrome P-450 CYP3A/chemistry/*metabolism ; Cytoplasm/*enzymology ; Humans ; Microsomes, Liver/*enzymology

Animals ; Cytoplasm ; metabolism ; Endoplasmic Reticulum, Rough ; metabolism ; Golgi Apparatus ; metabolism ; Humans ; Protein Transport ; Ricin ; chemistry ; pharmacokinetics ; therapeutic use

Histochemical, immunohistochemical and ultrastructural studies were performed on cases of hepatocellular carcinoma (HCC) with pale bodies (PB). HCC containing PBs was observed in 3 (5.5%) of 55 consecutively resected HCC cases. Histologically, a large number of hepatocytes displayed pale or eosinophilic staining of the cytoplasm, resulting in ground-glass appearance. They were aggregated in nodular pattern, or diffusely intermixed with other malignant hepatocytes. PBs were negative for periodic-acid Schiff and Masson's trichrome staining. The inclusions showed a strong positive reaction for fibrinogen and some of them were weakly positive for albumin but negative for hepatitis B surface antigen, hepatitis B core antigen, alpha-fetoprotein and alpha-1-antitrypsin. Ultrastructurally, PBs were membrane-bound and contained granular materials of moderate electron density, and were closely related to dilated rough endoplasmic reticulum. These findings support that PBs are secretory fibrinogen accumulated in cystic ER and that such intracellular accumulation possibly reflects a defective transport of fibrinogen.
Albumins/analysis ; Carcinoma, Hepatocellular/pathology* ; Cytoplasm/ultrastructure ; Cytoplasm/pathology ; Cytoplasm/chemistry ; Endoplasmic Reticulum, Rough/ultrastructure ; Endoplasmic Reticulum, Rough/pathology ; Endoplasmic Reticulum, Rough/chemistry ; Fibrinogen/analysis ; Human ; Inclusion Bodies/ultrastructure ; Inclusion Bodies/pathology* ; Inclusion Bodies/chemistry ; Liver Neoplasms/pathology* ; Male ; Microscopy, Electron ; Middle Age ; Periodic Acid-Schiff Reaction

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

MicroRNAs (miRNAs) are conserved small non-coding RNAs that play an important role in the regulation of gene expression and participate in a variety of biological processes. The biogenesis of miRNAs is tightly controlled at multiple steps, such as transcription of miRNA genes, processing by Drosha and Dicer, and transportation of precursor miRNAs (pre-miRNAs) from the nucleus to the cytoplasm by exportin-5 (XPO5). Given the critical role of nuclear export of pre-miRNAs in miRNA biogenesis, any alterations of XPO5, resulting from either genetic mutation, epigenetic change, abnormal expression level or posttranslational modification, could affect miRNA expression and thus have profound effects on tumorigenesis. Importantly, XPO5 phosphorylation by ERK kinase and its cis/trans isomerization by the prolyl isomerase Pin1 impair XPO5's nucleo-to-cytoplasmic transport ability of pre-miRNAs, leading to downregulation of mature miRNAs in hepatocellular carcinoma. In this review, we focus on how XPO5 transports pre-miRNAs in the cells and summarize the dysregulation of XPO5 in human tumors.
Carcinoma, Hepatocellular ; genetics ; metabolism ; Cell Nucleus ; metabolism ; Cytoplasm ; metabolism ; Humans ; Karyopherins ; chemistry ; metabolism ; physiology ; Liver Neoplasms ; genetics ; metabolism ; MicroRNAs ; chemistry ; metabolism ; NIMA-Interacting Peptidylprolyl Isomerase ; Neoplasms ; genetics ; metabolism ; RNA Precursors ; chemistry ; metabolism ; RNA Transport

Animals ; Cell Communication ; Cell Transformation, Neoplastic ; Connexins ; genetics ; metabolism ; Cytoplasm ; metabolism ; Gap Junctions ; chemistry ; classification ; metabolism ; physiology ; Gene Expression Regulation, Neoplastic ; Humans ; Mutation ; Neoplasms ; etiology ; metabolism ; pathology

An adult female dog was presented for evaluation of mammary gland masses. Complete blood count and serum chemistry data were within normal limits. Fine-needle aspiration cytology of the mammary masses revealed clusters of malignant epithelial cells with clear cytoplasmic vacuoles. Based on histopathological findings, a diagnosis of lipid-rich mammary carcinoma was made. Approximately 5 weeks after surgical removal, the tumor recurred at the surgery site and metastasis to the tibia was detected. Due to the poor prognosis and deterioration of the condition, the dog was euthanized.
Adult ; Animals ; Biopsy, Fine-Needle ; Blood Cell Count ; Chemistry ; Cytoplasm ; Diagnosis ; Dogs* ; Epithelial Cells ; Female ; Humans ; Mammary Glands, Human ; Neoplasm Metastasis ; Prognosis ; Tibia ; Vacuoles

ORF3 protein, the single accessory protein encoded by porcine epidemic diarrhea virus (PEDV), is related to viral pathogenicity. In order to determine the cytoplasmic location signal of PEDV ORF3, we constructed a series of recombinant plasmids carrying full-length or truncated segments of PEDV DR13 ORF3 protein. When the acquired plasmids were transfected into Vero cells, expression and distribution of the EGFP-fused full-length ORF3 protein and its truncated forms in the cells were observed by laser confocal microscopy. The results showed that ORF3 protein or their truncated forms containing 40-91 aa segment including two transmembrane domains were localized in the cytoplasm, whereas ORF3 truncated peptides without the 40-91 aa segment were distributed in the whole cell (in both cytoplasm and nucleus). This suggests that the 40-91 aa is the key structural domain determining cytoplasmic location of PEDV ORF3 protein. The discovery provides reference for further clarifying intracellular transport and biological function of PEDV ORF3 protein.
Amino Acid Sequence ; Animals ; Chlorocebus aethiops ; Coronavirus Infections ; virology ; Cytoplasm ; virology ; Porcine epidemic diarrhea virus ; genetics ; Protein Domains ; Swine ; Vero Cells ; Viral Proteins ; chemistry ; metabolism