The chloroplast thylakoid ATP/ADP carrier (TAAC) belongs to the mitochondrial carrier superfamily, and supplies the thylakoid with ATP in exchange for ADP. A recent study in Plant Physiology showed that TAAC mutants exhibit abnormal growth that is apparently caused by disturbances in the photosystem II (PSII). For investigation of the PSII the study utilized an antibody against the major light-harvesting chlorophyll a/b protein complex (LHC-II) that is available on antibodies-online.