Abstract 4447: Generation of a conditional S194A mutant RalA allele in mice

Abstract

Abstract The Ras family of small-GTPases represent the most frequently mutated oncogene in human cancer. Oncogenic Ras activates RalGEFs, which converts the Ras like small GTPases RalA and RalB to their active GTP-bound state to promote tumorigenesis. Despite being highly related, RalA generally tends to be more important in tumor growth while RalB has been implicated in metastasis. In regard to a mechanism underlying these functional differences, we note that RalA, but not RalB, is phosphorylated by the mitotic kinase AuroraA at Serine 194, and this phosphorylation is necessary for Ras-driven tumorigenesis. This phosphorylation has been found to result in an accumulation of RalA in mitochondrial fractions and an increase in mitochondrial fission and segregation during cytokinesis. Despite these encouraging observations, the role of this seemingly critical phosphorylation event in an actual in vivo setting was completely unknown. Thus, to determine the physiological consequence of this phosphorylation in vivo, we generated a mouse with a Cre-inducible S194A conditional Rala allele. We now report that these mice express wild-type RalA in the absence of Cre, but upon Cre-mediated recombination, convert wild-type exon 5 of Rala to one encoding the S194A mutant version. We propose to next investigate the consequences of blocking this critical posttranslational modification on normal development and on oncogenic Kras-driven tumorigenesis. Citation Format: Matthew S. Crowe, Christopher M. Counter. Generation of a conditional S194A mutant RalA allele in mice. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4447. doi:10.1158/1538-7445.AM2014-4447