Nuclear targeting of beta-catenin is an obligatory step in Wnt signal transduction, but the factors that control import and export remain to be clarified. In this issue, Hendriksen et al. (p. 785) show that the RanBP3 export factor antagonizes beta-catenin/T cell factor (TCF) transcription by targeting the signaling-competent form of beta-catenin. We speculate that cells may use multiple export...

While in the history of generative grammar the distinction between Obligatory Control and Non-obligatory Control has been high on the agenda for a long time, recently a fresh idea has been thrust into the limelight posing a real challenge to any theory of control (cf. Landau 2000). It has been proved that the relation between PRO and its controller is not always one of identity, i.e. the refere...

Mitotic inheritance of gene function is obligatory to sustain biological control. Emerging evidence suggests that epigenetic mechanisms are linked to transmission of cell fate, lineage commitment, and maintenance of cellular phenotype in progeny cells. Mechanisms of epigenetic memory include gene silencing by DNA methylation, transcriptional regulation by histone modifications, regulation of ge...

The aim of this paper is to develop a representation of control that does not require a PRO-subject. I first analyse obligatory control using a de-compositional analysis of u-roles, according to which u-roles are divided into two selectional requirements. The resulting theory makes the same predictions as one based on PRO, yet avoids dependence on this ill-defined empty category. I then concent...