How cells acquire complex shapes is a fundamental question in biology. Lauster et al. show that PHGAP/RENs associate with cortical microtubules preferentially along anticlinal cell faces, and they facilitate the spatially distinct deactivation of ROP2 in indentations. This interplay is essential for multipolarity of epidermal pavement cells.

The PII protein is an evolutionary, highly conserved regulatory protein found in both bacteria and higher plants. In bacteria, it modulates the activity of several enzymes, transporters, and regulatory factors by interacting with them and thereby regulating important metabolic hubs, such as carbon/nitrogen homeostasis. More than two decades ago, the PII protein was characterized for the first time in plants, but its physiological role is still not sufficiently resolved. To gain more insights into the function of this protein, we investigated the interaction behavior of AtPII with candidate proteins by BiFC and FRET/FLIM in planta and with GFP/RFP traps in vitro. In the course of these studies, we found that AtPII interacts in chloroplasts with itself as well as with known interactors such as N-acetyl-L-glutamate kinase (NAGK) in dot-like aggregates, which we named PII foci. In these novel protein aggregates, AtPII also interacts with yet unknown partners, which are known to be involved in plastidic protein degradation. Further studies revealed that the C-terminal component of AtPII is crucial for the formation of PII foci. Altogether, the discovery and description of PII foci indicate a novel mode of interaction between PII proteins and other proteins in plants. These findings may represent a new starting point for the elucidation of physiological functions of PII proteins in plants.

The PII protein is an evolutionary highly conserved regulatory protein from bacteria to higher plants. In bacteria it modulates the activity of several enzymes, transporters and regulatory factors by interacting with them and thereby regulating important metabolic hubs like carbon/nitrogen homeostasis. More than two decades ago the PII protein was characterized for the first time in plants, but its physiological role is still not sufficiently resolved. To gain more insights into the function of this protein, we investigated the interaction behaviour of AtPII with candidate proteins by BiFC and FRET/FLIM in planta and with GFP/RFP traps in vitro. In the course of these studies we found that AtPII interacts in chloroplasts with itself as well as with known interactors like NAGK in dot-like aggregates, which we named PII foci. In these novel protein aggregates AtPII interacts also with yet unknown partners, which are known to be involved in plastidic protein degradation. Further studies revealed that the C-terminal part of AtPII is crucial for the formation of PII foci. Altogether, the presented results indicate a novel mode of interaction for PII proteins with other proteins in plants, which may be a new starting point for the elucidation of physiological functions of PII proteins in plants.

The success of REACh will depend on whether or not the actors are willing and able to adopt the roles allocated to them under the new regime. Yet it would be naive to assume that the simple fact of enacting the Regulation will be sufficient to effect the necessary changes in the behaviour of the responsible parties. Within this context, a study on behalf of the German Federal Environmental Agency (Umweltbundesamt – UBA) was performed. The study’s initial hypothesis was that support - in the form of (technical and organisational) guidance specific to each type of economic actor - can help to push forward the necessary innovation and co-operation processes to implement REACh in the intended way. Thus, transaction costs for each actor can be kept to a minimum and obstacles overcome. This also supports the central, structural objective of REACh to establish a “learning system”, particularly with regard to the interaction occurring between the producers and users of industrial chemicals. To this end, sufficient regulatory (dis)incentives are essential. For this reason, the question of possible amendments to the current draft of the Regulation was also addressed.

Participation by its very nature is iterative, meaning Participatory Action Research (PAR) must be responsive to the way participation manifests and what actions emerge from this participation. In the article that follows, we share the complex and intertwined stories of PAR in action in two social movement contexts in Ghana, as well as the conditions that led to inaction in these two stories. This article builds on previous related work, where PAR was described as “moving with the movement” (Langdon & Larweh, 2015), and describes the complexities of trying to move with the movement as conditions and relationships change over time. By sharing challenges and achievements that have emerged from the movement and research, we illustrate how moving with the movement has resulted in rich and unanticipated learnings.