RESUMEN
Dimerization of SRC kinase adaptor phosphoprotein 2 (SKAP2) induces an increase of binding for most SRC kinases suggesting a fine-tuning with transphosphorylation for kinase activation. This work addresses the molecular basis of SKAP2-mediated SRC kinase regulation through the lens of their interaction capacities. By combining a luciferase complementation assay and extensive site-directed mutagenesis, we demonstrated that SKAP2 interacts with SRC kinases through a modular organization depending both on their phosphorylation-dependent activation and subcellular localization. SKAP2 contains three interacting modules consisting in the dimerization domain, the SRC homology 3 (SH3) domain, and the second interdomain located between the Pleckstrin homology and the SH3 domains. Functionally, the dimerization domain is necessary and sufficient to bind to most activated and myristyl SRC kinases. In contrast, the three modules are necessary to bind SRC kinases at their steady state. The Pleckstrin homology and SH3 domains of SKAP2 as well as tyrosines located in the interdomains modulate these interactions. Analysis of mutants of the SRC kinase family member hematopoietic cell kinase supports this model and shows the role of two residues, Y390 and K7, on its degradation following activation. In this article, we show that a modular architecture of SKAP2 drives its interaction with SRC kinases, with the binding capacity of each module depending on both their localization and phosphorylation state activation. This work opens new perspectives on the molecular mechanisms of SRC kinases activation, which could have significant therapeutic impact.
Asunto(s)
Dominios Homologos src , Familia-src Quinasas , Familia-src Quinasas/metabolismo , Fosfoproteínas/metabolismo , FosforilaciónRESUMEN
BACKGROUND: Elderly cancer patients often experience cognitive difficulties that can affect their quality of life and autonomy. However, they are rarely included in clinical trials, and only one study has explored the feasibility of cognitive training in this population. While digital cognitive training has been successful in improving cognition in younger patients, its feasibility in elderly patients requires evaluation. OBJECTIVES: This feasibility study primarily focused on evaluating patients' ability to use digital cognitive stimulation (usability). Secondary objectives were to evaluate acceptability, adherence, and satisfaction with regard to digital cognitive stimulation in elderly breast cancer patients. METHODS: Elderly breast cancer patients at least 70 years old who were receiving cancer treatment (chemotherapy, targeted therapy, and/or radiotherapy) were recruited. Cognitive complaints were evaluated at baseline using the Functional Assessment of Cancer Therapy-Cognitive Function scale (FACT-Cog). Participants were invited to attend three 20-minute sessions of digital cognitive stimulation using HappyNeuron PRESCO software App on tablets, with the first session being supervised by a neuropsychologist and the two others being performed independently either at home or at the cancer center. We hypothesized that participants would spend 10 of the 20 min of the given time with the tablet completing exercises (training time). Thus, the usability of digital cognitive stimulation was defined as completing at least three exercises during the training time (10 min) of one of the two training sessions in autonomy. The proportion of patients who agreed to participate (acceptability) and completion of planned sessions (adherence) were also estimated. Satisfaction was evaluated post-intervention through a self-report questionnaire. RESULTS: 240 patients were initially screened, 60% (n = 145) were eligible and 38% agreed to participate in the study. Included patients (n = 55) had a mean age of 73 ± 3 years, 96% an ECOG score of 0-1 and were undergoing radiotherapy (64%), and/or chemotherapy (47%) and/or targeted therapy (36%) for stage I-II breast cancer (79%). Most patients reported significant cognitive complaints (82%) and 55% had previous experience with digital tools (n = 30). The usability rate was 92%, with 46 out of 50 evaluable participants completing at least three exercises during the training time. The adherence rate was 88%, with 43/50 participants completing all planned sessions. Participants were largely satisfied with the cognitive intervention format (87%). They preferred to complete sessions at the cancer center under the supervision of the neuropsychologist than alone at home (90%). CONCLUSIONS: The high level of usability, adherence and satisfaction in this study shows for the first time the feasibility of digital cognitive stimulation in cancer patients older than 70 years. However, the intervention should be proposed only to patients reporting cognitive complaints and should be structured and supervised to improve acceptability and adherence. TRIAL REGISTRATION: ClinicalTrials identifier: NCT04261153, registered on 07/02/2020.