The Open University ’ s repository of research publications and other research outputs CAPRI and RASAL impose different modes of information processing on Ras due to contrasting temporal filtering

(2005). CAPRI and RASAL impose different modes of information processing on Ras due to contrasting temporal filtering of Ca2+. Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online's data policy on reuse of materials please consult the policies page. he versatility of Ca 2 ϩ as a second messenger lies in the complex manner in which Ca 2 ϩ signals are generated. How information contained within the Ca 2 ϩ code is interpreted underlies cell function. Recently, we identified CAPRI and RASAL as related Ca 2 ϩ-triggered Ras GTPase-activating proteins. RASAL tracks agonist-stimulated Ca 2 ϩ oscillations by repetitively associating with the plasma membrane, yet CAPRI displays a long-lasting Ca 2 ϩ-triggered translocation that is refractory to cytosolic Ca 2 ϩ oscillations. CAPRI behavior is Ca 2 ϩ-and C2 domain–dependent but sustained recruitment is pre-T dominantly Ca 2 ϩ independent, necessitating integration of Ca 2 ϩ by the C2 domains with agonist-evoked plasma membrane interaction sites for the pleckstrin homology domain. Using an assay to monitor Ras activity in real time, we correlate the spatial and temporal translocation of CAPRI with the deactivation of H-Ras. CAPRI seems to low-pass filter the Ca 2 ϩ signal, converting different intensities of stimulation into different durations of Ras activity in contrast to the preservation of Ca 2 ϩ frequency information by RASAL, suggesting sophisticated modes of Ca 2 ϩ-regulated Ras deactivation.