The project will support a collaboration between the biological chemistry group (CORE) at the University in Stavanger and the Biotechnology Department at Kakatiya University in India for exchange of knowledge and staff. Both universities share an interest in basic plant science as well as a common interest in specific plants of agricultural importance, therefore both Arabidopsis and tomato will be used as model plants. The first subject for common efforts is the investigation of regulatory subunits of pro tein phosphatase 2A (PP2A). PP2A is an important group of protein phosphatases that regulate growth and development. Canonical PP2As are heterotrimeric complexes consisting of a catalytic subunit (C), a scaffolding subunit (A), and a regulatory subunit (B ). The regulatory B subunits play an important role in conferring substrate specificity to the full complex and determining subcellular localization of PP2As. In the model plant Arabidopsis, at least 17 different genes encoding B subunits are present, but their physiological roles and targets are hardly known. The B subunits are divided into three subgroups, B, B' and B''. Especially the regulatory B'' subunits will be investigated in this project. The results will contribute to the understanding of regul atory networks involving protein phosphatase 2A and directing growth and development.