Mitotic spindle association of TACC3 requires Aurora-A-dependent stabilization of a cryptic α-helix.

Aurora-A regulates the recruitment of TACC3 to the mitotic spindle through a phospho-dependent interaction with clathrin heavy chain (CHC). Here, we describe the structural basis of these interactions, mediated by three motifs in a disordered region of TACC3. A hydrophobic docking motif binds to a previously uncharacterized pocket on Aurora-A that is blocked in most kinases. Abrogation of the docking motif causes a delay in late mitosis, consistent with the cellular distribution of Aurora-A complexes. Phosphorylation of Ser558 engages a conformational switch in a second motif from a disordered state, needed to bind the kinase active site, into a helical conformation. The helix extends into a third, adjacent motif that is recognized by a helical-repeat region of CHC, not a recognized phospho-reader domain. This potentially widespread mechanism of phospho-recognition provides greater flexibility to tune the molecular details of the interaction than canonical recognition motifs that are dominated by phosphate binding.

Cell cycle regulation by the NEK family of protein kinases.

Genetic screens for cell division cycle mutants in the filamentous fungus Aspergillus nidulans led to the discovery of never-in-mitosis A (NIMA), a serine/threonine kinase that is required for mitotic entry. Since that discovery, NIMA-related kinases, or NEKs, have been identified in most eukaryotes, including humans where eleven genetically distinct proteins named NEK1 to NEK11 are expressed. Although there is no evidence that human NEKs are essential for mitotic entry, it is clear that several NEK family members have important roles in cell cycle control. In particular, NEK2, NEK6, NEK7 and NEK9 contribute to the establishment of the microtubule-based mitotic spindle, whereas NEK1, NEK10 and NEK11 have been implicated in the DNA damage response. Roles for NEKs in other aspects of mitotic progression, such as chromatin condensation, nuclear envelope breakdown, spindle assembly checkpoint signalling and cytokinesis have also been proposed. Interestingly, NEK1 and NEK8 also function within cilia, the microtubule-based structures that are nucleated from basal bodies. This has led to the current hypothesis that NEKs have evolved to coordinate microtubule-dependent processes in both dividing and non-dividing cells. Here, we review the functions of the human NEKs, with particular emphasis on those family members that are involved in cell cycle control, and consider their potential as therapeutic targets in cancer.

Radiation Safety Awareness Among Non-radiology Staff at Tabuk Hospitals, Saudi Arabia.

BACKGROUND: Insufficient understanding of radiation safety contributes to heightened exposure vulnerability among patients and medical personnel. OBJECTIVES: This study assessed radiation safety awareness among non-radiology staff at Tabuk hospitals, Saudi Arabia. METHODS: This cross-sectional study included 203 non-radiology staff from the King Salman Armed Forces, King Fahad Specialist, and King Khaled Hospitals in Tabuk City, Saudi Arabia. A self-administered, structured questionnaire was used. Regression analysis was used to detect variables affecting radiation safety awareness. RESULTS: According to Bloom's cut-off categories for knowledge, most non-radiologists at Tabuk hospitals (76%) had low awareness levels. Having a moderate-to-high knowledge level regarding radiation safety was significantly associated with being a physician (p = 0.004), having a longer length of service (p = 0.001), having attended a radiation protection and safety course (p = 0.049), and increased frequency of ordering imaging per day (p < 0.001). Gender had no significant effect on the knowledge level (p = 0.854). Multivariate regression analysis revealed that the daily frequency of ordering images was the only independent significant factor associated with having a moderate-to-high level of knowledge (OR: 6.222, 95% CI: 2.706-14.308, p < 0.001). CONCLUSIONS: Non-radiologists in Tabuk hospitals have low awareness of radiation safety. Strong associations were noticed between awareness level and being a physician, having clinical experience, attending a radiation protection and safety course, and increasing the frequency of ordering imaging daily. Training courses about the hazards of radiation and the safety measures could lower the frequency of daily exposure to radiation.

Prevalence of Low Back Pain Among University Attendants in Tabuk City During 2023: A Cross-Sectional Study in Saudi Arabia.

BACKGROUND: College students are at a higher risk of suffering low back pain (LBP). Assessing the magnitude of the problem and the associated risk factors can help reduce the suffering and disability in future doctors. AIM: This study was conducted to investigate the prevalence and related factors of LBP among medical students in the University of Tabuk and emphasize the need for targeted interventions that could help alleviate the burden of LBP among the students and improve their quality of life. METHODS: This cross-sectional study used an online well-structured, self-report questionnaire to collect the respondents' data. The questionnaire explored the participants' sociodemographic factors, lifestyle, and the severity of LBP-related disability using the modified Oswestry Low Back Pain Disability Questionnaire (Oswestry Disability Index (ODI)) score. RESULTS: The prevalence rate of LBP was 26.8%. The independent factors that significantly increased the probability of LBP included overweight/obesity (odds ratio (OR): 1.696, 95% confidence interval (CI): 1.086 to 2.648, p = 0.020) and stretching exercises (OR: 1.784, 95% CI: 1.104 to 2.883, p = 0.018). The independent predictors that significantly increased the severity of ODI included married marital status (p = 0.007), back surgery (p = 0.031), and higher pain intensity (p < 0.001). CONCLUSIONS: We found that the prevalence rate of LBP among our sample was around 26%. This rate is approximate to the rates reported in previous studies. Furthermore, the activities most affected by LBP were sitting, standing, and lifting. Future studies should explore other risk factors and attempt to determine the onset of pain. A longitudinal study design is recommended to identify the onset of developing LBP.

Bloody Aggressive: A Case Report on a Fungating Breast Mass in a Paraplegic Requiring Emergency Mastectomy.

Fungating malignant lesions pose a huge deal of agony to the patients. Their management is also deemed as difficult by most physicians. This report describes a case of a 45-year-old paraplegic female with delayed presentation of a very aggressive fungating left breast mass, which was diagnosed as invasive ductal carcinoma. The uncontrollable hemorrhage had the surgeons succumb to the option of emergency mastectomy as a palliative treatment to save the life of the patient. Hence, we infer that the emergency mastectomy in a hemorrhagic fungating breast lesion can be life-saving and can be performed with little to no risk to the patient. Such a procedure, surprisingly, has never been documented in the surgical literature before.

Frequency of Extensively Drug-Resistant Gram-Negative Pathogens in a Tertiary Care Hospital in Pakistan.

Background Gram-negative bacteria are frequently involved in nosocomial infections. These bacteria have a particular tendency to develop antibiotic resistance and may become extensively drug-resistant (XDR). This study aimed to detect the prevalence of XDR Gram-negative bacteria in a tertiary care hospital in Pakistan. Materials and methods Clinical samples were obtained from patients admitted to different inpatient wards and sent for microbial analysis and culture. Antibiotic susceptibility testing of isolates was performed by the disk diffusion method to detect XDR strains. Results Antibiotic susceptibility patterns of a total of 673 clinical samples were studied. Of all bacterial isolates, 64% were extensively drug-resistant. Klebsiella pneumoniae had the highest percentage of XDR isolates (68.4%), followed by Pseudomonas aeruginosa (67.6%) and Escherichia coli (56.1%). Most XDR pathogens were isolated from the burn unit (87.7%), followed by the intensive care unit (69.2%) and surgical unit (68.9%). Conclusions The rate of extensive drug-resistance is alarmingly high, which calls for strict surveillance and control measures to prevent the development of further resistance. Proper sanitation and rational prescription of antibiotics should be ensured.

Mitotic phosphorylation regulates Hsp72 spindle localization by uncoupling ATP binding from substrate release.

Hsp72 is a member of the 70-kDa heat shock family of molecular chaperones (Hsp70s) that comprise a nucleotide-binding domain (NBD) and a substrate-binding domain (SBD) connected by a linker that couples the exchange of adenosine diphosphate (ADP) for adenosine triphosphate (ATP) with the release of the protein substrate. Mitotic phosphorylation of Hsp72 by the kinase NEK6 at Thr66 located in the NBD promotes the localization of Hsp72 to the mitotic spindle and is required for efficient spindle assembly and chromosome congression and segregation. We determined the crystal structure of the Hsp72 NBD containing a genetically encoded phosphoserine at position 66. This revealed structural changes that stabilized interactions between subdomains within the NBD. ATP binding to the NBD of unmodified Hsp72 resulted in the release of substrate from the SBD, but phosphorylated Hsp72 retained substrate in the presence of ATP. Mutations that prevented phosphorylation-dependent subdomain interactions restored the connection between ATP binding and substrate release. Thus, phosphorylation of Thr66 is a reversible mechanism that decouples the allosteric connection between nucleotide binding and substrate release, providing further insight into the regulation of the Hsp70 family. We propose that phosphorylation of Hsp72 on Thr66 by NEK6 during mitosis promotes its localization to the spindle by stabilizing its interactions with components of the mitotic spindle.

EML4-ALK Variants: Biological and Molecular Properties, and the Implications for Patients.

Since the discovery of the fusion between EML4 (echinoderm microtubule associated protein-like 4) and ALK (anaplastic lymphoma kinase), EML4-ALK, in lung adenocarcinomas in 2007, and the subsequent identification of at least 15 different variants in lung cancers, there has been a revolution in molecular-targeted therapy that has transformed the outlook for these patients. Our recent focus has been on understanding how and why the expression of particular variants can affect biological and molecular properties of cancer cells, as well as identifying the key signalling pathways triggered, as a result. In the clinical setting, this understanding led to the discovery that the type of variant influences the response of patients to ALK therapy. Here, we discuss what we know so far about the EML4-ALK variants in molecular signalling pathways and what questions remain to be answered. In the longer term, this analysis may uncover ways to specifically treat patients for a better outcome.

Loss of Nek11 Prevents G2/M Arrest and Promotes Cell Death in HCT116 Colorectal Cancer Cells Exposed to Therapeutic DNA Damaging Agents.

The Nek11 kinase is a potential mediator of the DNA damage response whose expression is upregulated in early stage colorectal cancers (CRCs). Here, using RNAi-mediated depletion, we examined the role of Nek11 in HCT116 WT and p53-null CRC cells exposed to ionizing radiation (IR) or the chemotherapeutic drug, irinotecan. We demonstrate that depletion of Nek11 prevents the G2/M arrest induced by these genotoxic agents and promotes p53-dependent apoptosis both in the presence and absence of DNA damage. Interestingly, Nek11 depletion also led to long-term loss of cell viability that was independent of p53 and exacerbated following IR exposure. CRC cells express four splice variants of Nek11 (L/S/C/D). These are predominantly cytoplasmic, but undergo nucleocytoplasmic shuttling mediated through adjacent nuclear import and export signals in the C-terminal non-catalytic domain. In HCT116 cells, Nek11S in particular has an important role in the DNA damage response. These data provide strong evidence that Nek11 contributes to the response of CRC cells to genotoxic agents and is essential for survival either with or without exposure to DNA damage.