Cell Cycle Proteins ; Microtubule-Associated Proteins

A growing body of evidence has indicated the important role of autophagy receptors in directing ubiquitinated or non-ubiquitinated cargos towards autophagy. Autophagy receptors bind to LC3 (microtubule-associated protein 1 light chain 3) on phagophore and autophagosome membranes, and recognize signals on cargoes in the delivery system of autophagy. However, the diverse domains in the receptor structures determine that their roles would never be limited to autophagy. Up to date, increasing numbers of the receptor proteins have been demonstrated to serve as a molecular link or switch participating in autophagic degradation, apoptosis or cell survival signals. Here, we highlight the non-autophagic roles of these receptor proteins to draw attention to this growing research topic.
Apoptosis ; Autophagy ; Humans ; Microtubule-Associated Proteins ; physiology ; Signal Transduction ; Ubiquitination

The present study involves a chronological and comparative analysis of both microtubule-associated protein 1A (MAP1A) and microtubule-associated protein 2 (MAP2) immunoreactivities in the striatum of both seizure resistant (SR) and seizure sensitive (SS) gerbil. The MAP1A immunoreactivity is weakly detected in perikarya of SR gerbils. However, MAP1A immunoreactivity is more accumulated in perikarya and dendrites in the pre-seizure group. At 30 min postictal, MAP1A immunoreactivity in the perikarya is decreased. At 3 hr postictal, MAP1A immunoreactivity in perikarya and dendrites is similarly decreased to the level of SR gerbils. The MAP2 immunoreactivity is weakly detected in the perikarya and dendrites of SR gerbils. However, MAP2 immunoreactivity is more accumulated in perikarya and dendrites. In particular, the neuropil between unstained fiber tracts obviously contains strong MAP2 immunoreactivity. At 30 min postictal, MAP2 immunoreactivity isn't almost observed in striatum. At 3 hr postictal, the MAP2 immunoreactivity is not different in the 30 min post -seizure groups but is only observed in the neuropil. However, at 12 hr postictal, the decrease of both MAP1A and MAP2 immunoreactivities had recovered to the pre -seizure level of SS gerbils. These results suggest that MAPs immunoreactivity in the striatum is different in SR and SS gerbils, and that this difference may be the results of seizure activity in this animal.
Animals ; Dendrites ; Epilepsy ; Gerbillinae* ; Microtubule-Associated Proteins* ; Microtubules* ; Neuropil ; Seizures*

OBJECTIVE: To show evidence of the autophagy in hippocampal nerve cells from rats with sepsis-associated encephalopathy (SAE) in vivo and to investigate the expression of microtubule-associated protein 1 light chain 3 (LC3). 
 METHODS: A rat model of sepsis was established by the cecal ligation and puncture (CLP). A total of 60 male Wistar rats (30 days old) were randomly divided into a sham group (n=10) and a CLP group (n=50). At 12 hours after CLP, the electroencephalogram (EEG) and somatosensory evoked potential (SEP) changes in rats were monitored and the neurobehavioral score was measured. According to the occurrence of SAE, the CLP group was further divided into an SAE(+) group and an SAE(-) group. Histopathological changes in hippocampus were observed by hematoxylin-eosin staining. An electron microscope was used to observe autophagosome formation and lysosome activation in the hippocampal nerve cells. Expressions of LC3-I and LC3-II protein were measured by Western blot. 
 RESULTS: Five of 50 rats in CLP group died in 12 hours after CLP. According to the low neurobehavioral score and abnormal EEG and SEP, 16 rats were diagnosed as SAE. The incidence of SAE was 35.56% (16/45). Compared with the sham group or the SAE(-) group, the frequency of α wave in SAE(+) group was significantly decreased at 12 hours after CLP, the δ wave increased, the P1 amplitude decreased, and the latency of SEP waves (P1 and N1) was prolonged (P<0.05). The morphology of hippocampal nerve cells was obvious in a status of edema. Pyramidal cells decreased significantly, even dissolved, and cell arrangement was in disorder in the SAE(+) group. But these cells were normal in the sham group and the SAE(-) group. The structure of hippocampal nerve cells was disordered, and the autophagy, granular matrix and square or rectangular crystals were found in the SAE(+) group. However, there was no autophagy both in the sham group and the SAE(-) group. LC3-II/LC3-I ratio in the hippocampal nerve cells was increased significantly at 12 hours after CLP in the SAE(+) group when compared with that in the sham or the SAE(-) group (P<0.05). 
 CONCLUSION There is autophagy in hippocampal nerve cells from rats with SAE and the LC3-II/LC3-I ratio is increased significantly.
Animals ; Autophagy ; Hippocampus ; Male ; Microtubule-Associated Proteins ; Neurons ; Rats ; Rats, Wistar ; Sepsis-Associated Encephalopathy

Cells selectively scavenge redundant or damaged mitochondria by mitophagy, which is an important mechanism of mitochondrial quality control. Recent studies have shown that mitophagy is mainly regulated by autophagy-related genes (Atgs) in yeast cells, while mitochondrial membrane associated proteins such as PTEN-induced putative kinase 1 (PINK1), NIX/BNIP3L, BNIP3, FUN14 domain containing 1 (FUNDC1), FKBP8/FKBP38, Bcl-2-like protein 13 (Bcl2L13), nucleotide binding domain and leucine-rich-repeat-containing proteins X1 (NLRX1), prohibitin 2 (PHB2) and lipids such as cardiolipin (CL) are the key mitophagic receptors in mammalian cells, which can selectively recognize damaged mitochondria, recruit them into isolation membranes by binding to microtubule-associated protein 1 light chain 3 (LC3) or γ-aminobutyric acid receptor-associated protein (GABARAP), and then fuse with lysosomes to eliminate the trapped mitochondria. This article reviews recent research progress of mitophagy-related receptor proteins.
Animals ; Apoptosis Regulatory Proteins ; Autophagy ; Microtubule-Associated Proteins ; Mitochondria ; Mitochondrial Proteins/genetics* ; Mitophagy ; Prohibitins

Humans ; Hypertension, Pulmonary ; metabolism ; Inhibitor of Apoptosis Proteins ; Microtubule-Associated Proteins ; metabolism

OBJECTIVETo investigate the effects of arsenic trioxide (As2O3) on the proliferation, differentiation and apoptosis of HL-60 cells in vitro and explore the underlying mechanisms.

METHODSAfter HL-60 cells were treated with different concentration of As2O3, the cell proliferation was determined by MTS/PES method, the differentiation state was detected by the nitroblue tetrazolium (NBT) reduction test; flow cytometry was used to analyze the apoptosis and expression of CD11b. In addition, SYBR Green real-time RT-PCR was used to measure the mRNA levels of C-FES, BCL-2, BAX, survivin , P21 and P27.

RESULTSAs2O3 could obviously inhibit the proliferation of HL-60 cells, and the effect was in dose- and time-dependent manners (r=-0.967; r=-0.954). Low concentration (0.1, 0.5 and 1.0 µmol/L) of As2O3 could significantly promote the differentiation of HL-60 cells, the cells exhibited a higher NBT-reducing ability and expressed far more CD11b antigens. High concentration (2.5 and 5.0 µmol/L) of As2O3 induced HL-60 cell apoptosis, but the ability of promoting differentiation decreased. The expression of C-FES mRNA significantly increased after being treated with As2O3 at the concentrations 1.0 and 5.0 µmol/L, and the former is more obvious, which confirmed that C-FES mRNA level paralleled the cell differentiation degree. Also, the expression of BCL-2 and survivin significantly decreased, while the expression of BAX, P21 and P27 was significantly upregulated in HL-60 cells after being treated with 5.0 µmol/L As2O3.

CONCLUSIONAs2O3 can significantly suppress cell proliferation, promote the differentiation and induce the apoptosis in HL-60 cells, and the mechanism of As2O3 anti-tumor activity may be involved in the regulation of C-FES, cell cycle and apoptosis-related genes.

OBJECTIVETo study the effect of calcitonin gene-related peptide (CGRP) on apoptosis and autophagy of mouse MC3T3-E1 osteoblast and their interaction and to further clarify protective mechanism of CGRP on osteoblasts.

METHODSMC3T3-E1 osteoblasts of mouse were cultured in vitro. Western blot and flow cytometry were used to detect expressions of microtubule-associated protein 1 light chain 3 (LC3) and P62 protein of MC3T3-E1 osteoblasts cultured with serum culture and serum-free (serum starvation) culture. Western blot was also used to detect expressions of LC3 and P62 protein of MC3T3-E1 osteoblast cultured at different concentrations (10⁻¹⁰, 10⁻⁹, 10⁻⁸, and 10⁻⁷ mol·L⁻¹) or without added CGRP. MC3T3-E1 osteoblasts were treated with 10⁻⁸ mol·L⁻¹ CGRP at different times (2, 6, 12, 24, 48, and 72 h), protein expression levels of LC3 were assessed by Western blot and flow cytometry, and changes in autophagosome in cells were detected by monodansylcadaverin staining. Autophagy inhibitor 3-methyladenine (3-MA) was used to pretreat MC3T3-E1 osteoblasts. Cells were then treated with or without CGRP for 24 h. Flow cytometry was used to detect apoptosis level.

RESULTSUnder serum starvation conditions, LC3Ⅱ expression and apoptosis of osteoblasts increased compared with that of serum culture. Under 3-MA pretreatment and serum starvation conditions, LC3Ⅱ expression of osteoblasts increased compared with that of serum culture (P<0.01). Compared with serum culture, serum starvation culture with or without CGRP significantly increased expression level of LC3 and reduced expression level of P62. LC3Ⅱ/Ⅰ of osteoblasts was the highest under serum starvation and 10⁻⁸ mol·L⁻¹ CGRP conditions. Serum starvation and 10⁻⁸ mol·L⁻¹ CGRP culture inhibited apoptosis of osteoblasts and promoted synthesis of autophagosome. Apoptosis of osteoblasts increased after 3-MA pretreatment, and CGRP reversed inhibitory effects of 3-MA CGRP on apoptosis.

CONCLUSIONSCGRP can increase autophagy of MC3T3-E1 osteoblasts under serum starvation conditions. CGRP may also inhibit apoptosis of MC3T3-E1 osteoblasts by promoting autophagy.
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OBJECTIVETo explore the role of microtubule-associated protein 2 (MAP-2) and nestin in the development of tongue muscles of human embryos and fetuses.

METHODSPV immunohistochemistry was used to detect the expressions of MAP-2 and nestin proteins in the tongue tissues of human embryos and fetuses at the second, third and fourth months of gestation.

RESULTSMAP-2 and nestin positivity was detected in the tongue muscles of human embryos at 2 to 4 months of gestation. In the embryos at the second month of gestation, no obvious MAP-2 positive cells were found in the tongue muscles; at 3 and 4 months, the number of MAP-2-positive cells in the tongue muscles was 24.14∓8.28 and 15.86∓3.89, with the expression intensity of 109.42∓11.62 and 124.27∓8.73, respectively. At 2, 3 and 4 months of gestation, the number of nestin-positive cells in the tongue muscles was 12.50∓3.17, 19.00∓7.63, and 22.80∓6.91, with expression intensity of 119.99∓24.02, 102.20∓11.76, and 98.24∓10.66, respectively. As the gestational age increased, the number of MAP-2-positive cell number continued to decline following a transient increase but the expression intensity kept increasing; nestin-positive cells increased continuously but the expression intensity kept decreasing in the embryonic or fetal tongue muscles.

CONCLUSIONMAP-2 and nestin proteins are involved in the regulation of the development of tongue muscles in human embryos and fetuses.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma (NHL), which is also a significantly heterogeneous disease. Survivin, a unique member of the inhibitor of apoptosis (IAP) family, is overexpressed in various cancers, including some types of lymphoma. It is found that inhibitor of apoptosis protein, survivin, plays an important role in the development and progression of DLBCL. Survivin is able to inhibit the cell apoptosis, and enhances the cell proliferation. Many studies showed that survivin may be considered as an independent unfavorable prognostic index of DLBCL. The poor prognostic cases early are screened in combination of survivin expression with International Prognostic Index (IPI), and improve the outcome of DLBCL. Survivin selectively expressed in tumor tissue, which provide an ideal target for tumor therapy. Modulation of survivin expression or function may provide a novel approach for experimental therapy in patients with DLBCL. In this review, the progress of study on mechanism of survivin protein, the survivin expression in DLBCL, its significance in diagnosis and therapy of DLBCL, and the prospective trend were summarized.
Apoptosis ; Humans ; Lymphoma, Large B-Cell, Diffuse ; metabolism ; pathology ; Microtubule-Associated Proteins ; biosynthesis