Abstract 2324: RhoGTPase-based regulation of cell motility by Plk4.
Notice bibliographique
Résumé
Abstract Background. Polo-like kinase 4 (Plk4) is a serine-threonine kinase that localizes to centrioles and is essential for centriole duplication. Plk4 expression is increased in colorectal, pancreas and breast cancers, and predicts resistance to therapy and poor survival. While centriolar overduplication and multipolar spindle formation is one mechanism by which dysregulated Plk4 can facilitate oncogenesis, our laboratory has found that Plk4 promotes migration and invasion of fibroblasts and of cancer cells by mechanisms currently under investigation. Haploid levels of Plk4 are associated with an increased incidence of improper cleavage furrow positioning during mitotic division, and we previously showed that RhoA is not adequately activated to effect proper actomyosin ring placement and contraction in Plk4 heterozygous murine embryonic fibroblasts (MEFs). We showed that the effect of Plk4 on RhoA activation is mediated by phosphorylation of the GEF Ect2 by Plk4 (Rosario et al., PNAS 2010). The small Rho GTPases RhoA, Rac1 and Cdc42 are known to regulate cell motility. We hypothesize that Plk4 promotes cancer cell motility by altering the activation of one or more of these RhoGTPases. Methods and Results: Pulldown experiments have shown a two-fold reduction in activated Rac1 in Plk4+/− as compared to Plk4+/+ MEFs. Depletion of Plk4 from wildtype MEFs using siPlk4 (confirmed by real time RT-PCR) reduced levels of activated Rac1, as compared to siLuciferase controls. Cdc42 activation was unaffected by Plk4. To determine the mechanism of the effect of Plk4 on Rho GTPase activation we investigated the upstream regulators that may be affected by Plk4, aside from Ect2. We scanned a library of 149 GEFs and GAPs cloned into the Creator system and identified 8 potential interactors (all GEFs) that contain the Plk4 consensus phosphorylation motif. We are evaluating these 8 candidates for physical interaction with Plk4 by co-transfection and co-immunoprecipitation from HeLa cells. By this method, we find that Plk4 physically interacts with the RhoA GEF ARHGEF1. To establish functional validation of this interaction, we are examining the phenotype of individually- and co- transfected HeLa cells. Transient transfection with Plk4 for 24h results in an arborized phenotype, while transfection with ARHGEF1 results in a rounded morphology; co-transfected cells display an intermediate phenotype. Immunofluorescence imaging shows co-localization of Flag-Plk4 and GFP-ARHGEF1 in lamellipodia, in keeping with a potential functional interaction. Whether the effect of ARHGEF1 on cell morphology is mediated through Rac1, RhoA, or both requires further investigation, as does the precise role of Plk4. Conclusions: Plk4 regulates the activation of Rac1 GTPase, and we demonstrate a physical and functional interaction of Plk4 with the Rac1 GEF ARHGEF1. Regulation of cancer cell motility via this pathway may contribute to promotion of invasion and metastasis by Plk4. Citation Format: Volha (Olga) Brashavitskaya, Karineh Kazazian, Rick Bagshaw, Carla O. Rosario, Francis S W Zih, Yosr Haffani, James W. Dennis, Tony J. Pawson, Carol J. Swallow. RhoGTPase-based regulation of cell motility by Plk4. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2324. doi:10.1158/1538-7445.AM2013-2324
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,012 | 0,006 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».