Protein Kinase A-Mediated Septin7 Phosphorylation Disrupts Septin Filaments and Ciliogenesis

Whole-Genome Resequencing Reveals Genetic Diversity and Growth Trait-Related Genes in Pinan Cattle

The breeding of high-quality beef cattle breeds is crucial for the development of animal husbandry, and whole-genome resequencing is widely applicated in the field of molecular breeding. Advantages in growth and reproductive traits exist in Pinan cattle compared with other cattle breeds, but there is limited research on its genomic mechanism. Using whole-genome resequencing, the genetic structure and genomic selection signatures in Pinan cattle were investigated in this study. Phylogenetic, cluster, and admixture analysis results indicated that Pinan cattle have a closer genetic relationship with Kholmogory cattle and China north cattle breeds. Through a selective sweep strategy, 207 and 54 candidate genes related to growth and reproduction and immunity, respectively, were identified in the Pinan cattle population. Given the crucial role of the glutamate-cysteine ligase catalytic (GCLC) gene in muscle antioxidative defense, the high frequency of allele T of the GCLC c.429 C>T locus in the Pinan cattle population might partially contribute to the advantages of Pinan cattle in growth performance. This study laid the foundation for the genetic improvement in Chinese local beef cattle and provide background for the studies on the growth and development of Pinan cattle.

Decoding post-translational modifications of mammalian septins

Septins are cytoskeletal GTPases that form nonpolar filaments and higher-ordered structures and they take part in a wide range of cellular processes. Septins are conserved from yeast to mammals but absent from higher plants. The number of septin genes vary between organisms and they usually form complex heteropolymeric networks. Most septins are known to be capable of GTP hydrolysis which may regulate septin dynamics. Knowledge on regulation of septin function by post-translational modifications is still in its infancy. In this review article, we highlight the post-translational modifications reported for the 13 human septins and discuss their implications on septin functions. In addition to the functionally investigated modifications, we also try to make sense of the complex septin post-translational modification code revealed from large-scale phospho-proteomic datasets. Future studies may determine how these isoform-specific and homology group specific modifications affect septin structure and function.

Phosphoregulation of the septin cytoskeleton in neuronal development and disease

Septins are highly conserved GTP-binding proteins that oligomerize and form higher order structures. The septin cytoskeleton plays an important role in cellular organization, intracellular transport, and cytokinesis. Kinase-mediated phosphorylation of septins regulates various aspects of their function, localization, and dynamics. Septins are enriched in the mammalian nervous system where they contribute to neurodevelopment and neuronal function. Emerging research has implicated aberrant changes in septin cytoskeleton in several human diseases. The mechanisms through which aberrant phosphorylation by kinases contributes to septin dysfunction in neurological disorders are poorly understood and represent an important question for future research with therapeutic implications. This review summarizes the current state of knowledge of the diversity of kinases that interact with and phosphorylate mammalian septins, delineates how phosphoregulation impacts septin dynamics, and describes how aberrant septin phosphorylation contributes to neurological disorders.

A biochemical view on the septins, a less known component of the cytoskeleton

The septins are a conserved family of guanine nucleotide binding proteins, often named the fourth component of the cytoskeleton. They self-assemble into non-polar filaments and further into higher ordered structures. Properly assembled septin structures are required for a wide range of indispensable intracellular processes such as cytokinesis, vesicular transport, polarity establishment and cellular adhesion. Septins belong structurally to the P-Loop NTPases. However, unlike the small GTPases like Ras, septins do not mediate signals to effectors through GTP binding and hydrolysis. The role of nucleotide binding and subsequent GTP hydrolysis by the septins is rather controversially debated. We compile here the structural features from the existing septin crystal- and cryo-EM structures regarding protofilament formation, inter-subunit interface architecture and nucleotide binding and hydrolysis. These findings are supplemented with a summary of available biochemical studies providing information regarding nucleotide binding and hydrolysis of fungal and mammalian septins.

UBC Mediated by SEPT6 Inhibited the Progression of Prostate Cancer

Background

Prostate cancer is one of the most common malignancies in men. Protein ubiquitination is an important mechanism for regulating protein activity and level in vivo. We aimed to study the mechanism of SEPT6 and UBC action in prostate cancer to identify new targets.

Methods

The ubiquitin-protein and the ubiquitin coding gene UBA52, UBA80, UBB, and UBC expressions were detected in clinical tissues and cells. Overexpression and knockdown of UBC were performed in prostate cancer DU145 cells. Cell Counting Kit 8 (CCK-8) assay was performed to detect cell proliferation. Cell cycle at 24 h was detected by flow cytometry. Clonal formation assay was used to measure cell clone number. Immunofluorescence (IF) was performed to detect the colocalization of SEPT6 and UBC in prostate cancer cells. Next, we overexpressed or knocked down SEPT6 expression in DU145 cells. Pearson correlation coefficient was applied to analyze the relationship between SEPT6 and UBC in prostate cancer tissue. oe-SEPT6+oe-UBC coexpressing cells were constructed to detect the upstream and downstream relationship between SEPT6 and UBC on prostate cancer cells. The tumor formation experiment was performed to explore SEPT6/UBC effect on prostate cancer.

Results

UBC was upregulated in prostate cancer tissues and cells. Overexpression of UBC promoted cell survival and proliferation. IF revealed the colocalization of SEPT6 and UBC in prostate cancer cells. UBC expression decreased after oe-SEPT6, while increased after sh-SEPT6, indicating that UBC was downstream of SEPT6. Pearson correlation coefficient analysis showed that SEPT6 was negatively correlated with UBC in prostate cancer tissues. SEPT6 as an upstream gene of UBC regulated prostate cancer cell behavior through UBC. The tumor formation experiment showed that SEPT6 could inhibit tumor growth.

Conclusion

In general, SEPT6 inhibited UBC expression, thereby reducing the overall ubiquitination level, affecting the expression level of downstream cell proliferation-related genes, and then affecting the progression of prostate cancer.