The CCR4-NOT complex is a highly conserved, multifunctional machinery controlling mRNA metabolism. Its components have been implicated in several aspects of mRNA and protein expression, including transcription initiation, elongation, mRNA degradation, ubiquitination, and protein modification. In this review, we will focus on the role of the CCR4-NOT complex in mRNA degradation. The complex contains two types of deadenylase enzymes, one belonging to the DEDD-type family and one belonging to the EEP-type family, which shorten the poly(A) tails of mRNA. We will review the present state of structure-function analyses into the CCR4-NOT deadenylases and summarize current understanding of their roles in mRNA degradation. We will also review structural and functional work on the Tob/BTG family of proteins, which are known to interact with the CCR4-NOT complex and which have been reported to suppress deadenylase activity in vitro.
Animals ; Humans ; Multiprotein Complexes ; chemistry ; genetics ; metabolism ; Protein Conformation ; RNA, Messenger ; genetics ; metabolism ; Transcription Factors ; chemistry ; genetics ; metabolism

The inflammasome is a group of multiprotein complexes in the cytoplasm, which can activate caspase-1 that mediates the maturation and release of IL-1β, IL-18, IL-33 and other pro-inflammatory cytokines.NALP1 (NACHT leucine-rich-repeat protein 1), also known as NLRP1, is the first one of the identified complex inflammasomes with definite ligands mainly involved in the activation of inflammasome assembly and the formation of apoptotic bodies. Moreover, it was also found that NLRP1 plays an important biological role in the development of acute leukemia, the bone marrow hematopoietic stem cell apoptosis and other blood diseases. This review briefly summarizes the structure, activation mechanism, regulation and the role of NLRP1 in the hematopoietic system.
Adaptor Proteins, Signal Transducing ; metabolism ; Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Cytokines ; Hematologic Diseases ; metabolism ; pathology ; Humans ; Inflammasomes ; Multiprotein Complexes

Binding Sites ; Histone-Lysine N-Methyltransferase ; chemistry ; metabolism ; Histones ; chemistry ; metabolism ; Humans ; Methylation ; Multiprotein Complexes ; chemistry ; metabolism ; Nuclear Proteins ; chemistry ; metabolism ; Protein Binding ; Protein Conformation ; Yeasts ; chemistry

OBJECTIVETo investigate the expression of CSN complex (COP9 signal some subunits) in the patients with acute promyelocytic leukemia (APL) and its significance in the ATRA-induced APL differentiation.

METHODSUsing the NB4 cells as a model, morphologic observation and myeloid differentiation marker CD11b detection were used to monitor ATRA-induced APL differentiation, the expression of CSN complex in cell differentiation was detected by Western blot and reverse transcription real time fluorescent quantitative PCR (RT-qPCR) method. RT-qPCR was also used to detect the relative expression level of COP9 signalosome subunits in the APL patients and remission after treatment.

RESULTSATRA could obviously enhance CD11b expression; the cell morphology showed obvious differentiation characteristics. During the differentiation, the expression of COP9 signalosome subunits was down-regulated by ATRA. Meanwhile, the CSN expression level in newly diagnosed APL patients was much higher than that in controls (non-leukemia) (P < 0.05). The level of CSN expression was obviously down-regulated when APL patients achieved complete remission.

CONCLUSIONThe high CSN expression level in APL patients can be down-regulated by ATRA. CSN complex may have a significant effect on the pathogenesis and therapy of APL.

COP9 Signalosome Complex ; Cell Differentiation ; Cell Line, Tumor ; Down-Regulation ; Humans ; Leukemia, Promyelocytic, Acute ; metabolism ; Multiprotein Complexes ; metabolism ; Peptide Hydrolases ; metabolism ; Tretinoin ; pharmacology

The long-term storage of memory requires the finely tuned coordination of intracellular signaling with the transcriptional, translational and epigenetic regulations of gene expression. Among the epigenetic mechanisms, however, we know relatively little about the involvement of chromatin remodeling-dependent control of gene expression in cognitive brain functions, compared with our knowledge of other such mechanisms (for example, histone modifications and DNA methylation). A few recent studies have implicated the Brm/Brg-associated factor (BAF) chromatin-remodeling complex, a mammalian homolog of the yeast Swi/Snf complex, in neuronal structural/functional plasticity and memory formation. The BAF complex was previously known to have a critical role in neurodevelopment, but these recent findings indicate that it also contributes to both cognitive functions in the adult brain and human mental disorders characterized by intellectual disability. In this review, we provide a brief overview of the BAF complexes, introduce recent research findings that link their functions to memory formation, and speculate on the yet-unknown molecular mechanisms that may be relevant to these processes.
Actins/metabolism ; Animals ; *Chromatin Assembly and Disassembly ; Chromosomal Proteins, Non-Histone/metabolism ; DNA-Binding Proteins/metabolism ; Gene Expression Regulation ; Humans ; Learning ; *Memory ; Multiprotein Complexes/metabolism ; Neurons/*metabolism ; Protein Binding ; Signal Transduction ; Transcription Factors/*metabolism

OBJECTIVETo explore the effects of K-ras gene mutation on colon cancer cell line Caco-2 metastasis by regulating E-cadherin/beta-catenin/p120 protein complex formation and RhoA protein activity.

METHODSK-ras wild-type colon cancer cell line Caco-2 was transiently transfected by phr-GFP vector (control group), transfected by mutant K-ras gene phr-K-ras (Val12) vector (transfection group), transfected by mutant K-ras gene phr-K-ras (Val12) vector and treated by specific MAPK pathway inhibitor PD98059 (MAPK inhibition group), or transfected by mutant K-ras gene phr-K-ras (Val12) vector and treated by specific PI-3K pathway inhibitor LY294002 (PI-3K inhibition group), respectively. Cell migration was tested by Transwell experiment. E-cadherin and beta-catenin protein expression and intracellular location were detected by cell immunofluorescence method. Intracellular p120 protein expression was detected by Western blot. beta-catenin protein level which combined with E-cadherin was detected by immunoprecipitation. RhoA activity was analyzed by Pull-down assay.

RESULTSThe Caco-2 cell migration rate was (19.8 +/- 5.6) % in transfection group, which was significantly higher than that in control group [(14.0 +/- 4.2) %] (P = 0.001) and in MAPK inhibition group [(15.8 +/- 1.2) %] (P = 0.044), but was not significantly different from that in PI-3K inhibition group [(17.5 +/- 2.8) %] (P = 0.095). Immunofluorescence method showed that the E-cadherin and beta-catenin stain located in the cell membrane decreased in transfection group. Western blot showed that the total intracellular p120 protein decreased in transfection group and PI-3K inhibition group. Immunoprecipitation data showed that beta-catenin protein level combined with E-cadherin decreased in transfection group and PI-3K group. Pull-down test showed that RhoA protein activity was up-regulated in transfection group.

CONCLUSIONK-ras gene mutation stimulates the migration of colon cancer cell Caco-2, which may be achieved by decreasing the E-cadherin/beta-catenin/p120 protein complex formation via MAPK pathway and increasing the RhoA protein activity.

Caco-2 Cells ; Cadherins ; metabolism ; Catenins ; metabolism ; Cell Movement ; Colonic Neoplasms ; metabolism ; pathology ; Genes, ras ; genetics ; Humans ; Multiprotein Complexes ; metabolism ; Mutation ; Neoplasm Metastasis ; Transfection ; beta Catenin ; metabolism ; rhoA GTP-Binding Protein ; metabolism

Humans ; Mechanistic Target of Rapamycin Complex 2/metabolism* ; Multiprotein Complexes/metabolism* ; Neural Stem Cells/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Rapamycin-Insensitive Companion of mTOR Protein/metabolism* ; TOR Serine-Threonine Kinases/metabolism*

MLL1 is a histone H3Lys4 methyltransferase and forms a complex with WDR5 and other components. It plays important roles in developmental events, transcriptional regulation, and leukemogenesis. MLL1-fusion proteins resulting from chromosomal translocations are molecular hallmarks of a special type of leukemia, which occurs in over 70% infant leukemia patients and often accompanies poor prognosis. Investigations in the past years on leukemogenesis and the MLL1-WDR5 histone H3Lys4 methyltransferase complex demonstrate that epigenetic regulation is one of the key steps in development and human diseases.
Animals ; DNA Methylation ; Epigenesis, Genetic ; Histone-Lysine N-Methyltransferase ; genetics ; metabolism ; Histones ; metabolism ; Humans ; Leukemia ; genetics ; metabolism ; Lysine ; metabolism ; Multiprotein Complexes ; genetics ; metabolism ; Myeloid-Lymphoid Leukemia Protein ; genetics ; metabolism ; Transcriptional Activation

OBJECTIVETo investigate the roles of the mammalian target of rapamycin-1 and -2 (mTORC1 and TORC2) in the proliferation and apoptosis of prostate cancer 22RV1 cells.

METHODSAfter silencing mTORC1 and TORC2, we examined the proliferation and apoptosis of prostate cancer 22RV1 cells by methylthiazol tetrazolium (MTT) assay and flow cytometry, respectively, and detected the expressions of the androgen receptor (AR) and Akt phosphorylation in the prostate cancer 22RV1 cells by Western blot after transfecting Raptor-siRNA and Rictor-siRNA to the 22RV1 cells.

RESULTSMTT showed that the prostate cancer 22RV1 cells had no significant change in the growth rate after mTORC1 silence (P > 0.05), but their proliferation was markedly inhibited after mTORC2 silence (P < 0.01). Flow cytometry revealed a dramatic increase in the apoptosis of the 22RV1 cells after mTORC1 silence (P < 0.01), but no obvious change after mTORC2 silence (P > 0.05). Western blot exhibited that mTORC1 silence significantly increased the expression of AR and Akt phosphorylation (P < 0.05), while mTORC2 silence markedly decreased them (P < 0.05).

CONCLUSIONmTORC2 is not only required for the survival of prostate cancer 22RV1 cells, but also a promising therapeutic target of prostate cancer.

Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Humans ; Male ; Mechanistic Target of Rapamycin Complex 1 ; Mechanistic Target of Rapamycin Complex 2 ; Multiprotein Complexes ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Receptors, Androgen ; metabolism ; Sirolimus ; pharmacology ; TOR Serine-Threonine Kinases ; metabolism

Mammalian target of rapamycin (mTOR) plays essential roles in cell proliferation, survival and metabolism by forming at least two functional distinct multi-protein complexes, mTORC1 and mTORC2. External growth signals can be received and interpreted by mTORC2 and further transduced to mTORC1. On the other hand, mTORC1 can sense inner-cellular physiological cues such as amino acids and energy states and can indirectly suppress mTORC2 activity in part through phosphorylation of its upstream adaptors, IRS-1 or Grb10, under insulin or IGF-1 stimulation conditions. To date, upstream signaling pathways governing mTORC1 activation have been studied extensively, while the mechanisms modulating mTORC2 activity remain largely elusive. We recently reported that Sin1, an essential mTORC2 subunit, was phosphorylated by either Akt or S6K in a cellular context-dependent manner. More importantly, phosphorylation of Sin1 at T86 and T398 led to a dissociation of Sin1 from the functional mTORC2 holo-enzyme, resulting in reduced Akt activity and sensitizing cells to various apoptotic challenges. Notably, an ovarian cancer patient-derived Sin1-R81T mutation abolished Sin1-T86 phosphorylation by disrupting the canonical S6K-phoshorylation motif, thereby bypassing Sin1-phosphorylation-mediated suppression of mTORC2 and leading to sustained Akt signaling to promote tumorigenesis. Our work therefore provided physiological and pathological evidence to reveal the biological significance of Sin1 phosphorylation-mediated suppression of the mTOR/Akt oncogenic signaling, and further suggested that misregulation of this process might contribute to Akt hyper-activation that is frequently observed in human cancers.
Adaptor Proteins, Signal Transducing ; metabolism ; Animals ; Humans ; Mechanistic Target of Rapamycin Complex 1 ; Mechanistic Target of Rapamycin Complex 2 ; Models, Biological ; Multiprotein Complexes ; metabolism ; Phosphorylation ; Phosphothreonine ; metabolism ; TOR Serine-Threonine Kinases ; metabolism