Expression Of Cytoskeleton Genes Research Articles

ASAP1 activates the IQGAP1/CDC42 pathway to promote tumor progression and chemotherapy resistance in gastric cancer

Abnormal expression and remodeling of cytoskeletal regulatory proteins are important mechanisms for tumor development and chemotherapy resistance. This study systematically analyzed the relationship between differential expression of cytoskeleton genes and prognosis in gastric cancer (GC). We found the Arf GTP-activating protein ASAP1 plays a key role in cytoskeletal remodeling and prognosis in GC patients. Here we analyzed the expression level of ASAP1 in tissue microarrays carrying 564 GC tissues by immunohistochemistry. The results showed that ASAP1 expression was upregulated in GC cells and can be served as a predictor of poor prognosis. Moreover, ASAP1 promoted the proliferation, migration, and invasion of GC cells both in vitro and in vivo. We also demonstrated that ASAP1 inhibited the ubiquitin-mediated degradation of IQGAP1 and thus enhanced the activity of CDC42. The activated CDC42 upregulated the EGFR-MAPK pathway, thereby promoting the resistance to chemotherapy in GC. Taken together, our results revealed a novel mechanism by which ASAP1 acts in the progression and chemotherapy resistance in GC. This may provide an additional treatment option for patients with GC.

Parkin deficiency exacerbates fasting-induced skeletal muscle wasting in mice

Parkinson’s Disease (PD) is a chronic and progressive neurodegenerative disease manifesting itself with tremors, muscle stiffness, bradykinesia, dementia, and depression. Mutations of mitochondrial E3 ligase, PARKIN, have been associated with juvenile PD. Previous studies have characterized muscle atrophy and motor deficits upon loss of functional Parkin in fly and rodent models. However, the mechanisms behind pathophysiology of Parkin deficient muscle remains to be elusive. Here, results suggested that knock down of Parkin significantly increases proteolytic activities in skeletal muscle cell line, the C2C12 myotubes. However, the atrogene levels increase moderately in Parkin deficient cell line. To further investigate the role of Parkin in skeletal muscle atrophy, Parkin knock out (KO) and wild type mice were subjected to 48 h starvation. After 48 h fasting, a greater reduction in skeletal muscle weights was observed in Parkin KO mice as compared to age matched wild type control, suggesting elevated proteolytic activity in the absence of Parkin. Subsequent microarray analyses revealed further enhanced expression of FOXO and ubiquitin pathway in fasted Parkin KO mice. Furthermore, a greater reduction in the expression of cytoskeleton genes was observed in Parkin KO mice following 48 h fasting. Collectively, these results suggest that Parkin deficiency exacerbates fasting-induced skeletal muscle wasting, through upregulating genes involved in catabolic activities in skeletal muscle.

Expression analysis of cellulose synthase and main cytoskeletal protein genes in flax (Linum usitatissimum L.).

Fiber flax is an important source of natural fiber and a comprehensive model for the plant fiber biogenesis studies. Cellulose-synthase (CesA) and cytoskeletal genes are known to be important for the cell wall biogenesis in general and for the biogenesis of flax fibers in particular. Currently, knowledge about activity of these genes during the plant growth is limited. In this study, we have investigated flax fiber biogenesis by measuring expression of CesA and cytoskeletal genes at two stages of the flax development (seedlings and stems at the rapid growth stage) in several flax subspecies (elongatum, mediterraneum, crepitans). RT-qPCR has been used to quantify the expression of LusСesA1, LusСesA4, LusСesA7, LusСesA6, Actin, and α-Tubulin genes in plant samples. We report that CesA genes responsible for the secondary cell wall synthesis (LusCesA4, LusCesA7) have different expression pattern compared with CesA genes responsible for the primary cell wall synthesis (LusCesA1, LusCesA6): an average expression of LusCesA4 and LusCesA7 genes is relatively high in seedlings and further increases in stems at the rapid growth stage, whereas an average expression of LusCesA1 and LusCesA6 genes decreases. Interestingly, LusCesA1 is the only studied gene with different expression dynamics between the flax subspecies: its expression decreases by 5.2-10.7 folds in elongatum and mediterraneum but does not change in crepitans subspecies when the rapid growth stage and seedlings are compared. The expression of cytoskeleton genes (coding actin and α-tubulin) is relatively stable and significantly higher than the expression of cellulose-synthase genes in all the studied samples.

Evaluating the temporal stability of stress-activated protein kinase and cytoskeleton gene expression in the Pacific reef corals Pocillopora damicornis and Seriatopora hystrix

The gastrodermal tissues of anthozoans that harbor endosymbiotic Symbiodinium experience light-dependent fluxes in dinoflagellate derived photosynthetic compounds that have the potential to impact the osmotic homeostasis of the animal. To explore this unusual osmoregulatory scenario, genes encoding proteins that play highly conserved roles in osmoregulation (mitogen-activated protein kinases, [MAPKs]) and the maintenance of the cytoskeleton ( ß-actin, tropomyosin, and α-tubulin) were quantified over diel cycles using quantitative real-time polymerase chain reaction. The expression of MAPK genes in Pocillopora damicornis increased at night, while the expression of cytoskeleton genes in Seriatopora hystrix decreased. The increase in P. damicornis MAPK expression may reflect host osmolyte production in response to reduced osmotic pressure at night. The concomitant decrease in expression of genes encoding cytoskeleton proteins at night is consistent with this interpretation, indicating reduced production of spatially demanding proteins under periods of intracellular crowding. However, the latter interpretation is confounded by the fact that molecularly-inferred Symbiodinium densities were found to be significantly greater at night in both corals, so changes in cytoskeletal gene expression may also reflect crowding to accommodate the greater density of these endosymbionts. In addition to providing insight into an unusual physiological attribute of photosynthetic endosymbioses, this study represents the first to measure gene behavior in field and cultured corals with a method that considers the dual-compartment nature of the associations.

Morphological changes of Vibrio parahaemolyticus under cold and starvation stresses

This study addresses morphological changes of Vibrio parahaemolyticus cells during the initial period of stress. Drastic changes occurred in cells under starvation with/without concomitant cold treatment for one to a few days. Under carbon starvation, rod-shaped cells became coccoid by reductive division, which was influenced by glucose/amino acid in the culture medium. Under concomitant cold and carbon starvation, cells entered the viable but nonculturable state and their shape changed from rod-like to coccoid with waning-shape and various aberrantly intermediates, such as club-shaped, budding, club-shaped with budding, dumbbell-shaped and rabbit-ear-like-shaped. Electron microscopy revealed characteristic features in the cells that were concomitantly stressed with cold and starved, such as densely stained peripheral part and lightly stained central part of cytoplasm, and a thick peptidoglycan cell wall in the temperature-upshifted cells. The expression of cytoskeleton genes, mreB, minE and ftsZ, was determined in a real-time quantitative reverse transcription-polymerase chain reaction, and results revealed a substantial decline in expression in cells under starvation (to 0.25 to 0.64 times that of the control) in the first 2 to 3 h, and a rapid upregulated expression in recovering cells. Alteration of the morphology of cells under such stresses may be associated with the expression of these cytoskeleton genes. This work demonstrates the uniqueness of concomitant cold and starvation treatment in V. parahaemolyticus. The details of the morphological changes may facilitate understanding of stress adaptation in bacteria.