Peroxisomes are involved in three important developmental stages within a plant life cycle. First, seedling establishment depends on the peroxisomal mobilization of fatty acids, whereas the transition to photoautotrophic growth requires metabolic adaptation of peroxisomes towards photorespiration. Finally, during leaf senescence peroxisomes contribute to fatty acid turnover of membrane lipids. The tight coordination of plant development and peroxisomal metabolism necessitate metabolite, cofactor and ion shuttling across the peroxisomal membrane. We are working on the characterization and regulation of peroxisomal solute transport proteins by combining biochemical and molecular approaches.