Component of an antenna complex or protein regulating the expression of such components. Antenna complexes are light-harvesting systems (LHC) which are protein-pigment complexes in or on photosynthetic membranes. LHCs receive radiant energy and transfer it to the reaction centers; an array of LHCs is often referred to as an "antenna". LHCs typically include one or more associated pigments (phycobilins, chlorophylls, bacteriochlorophylls and carotenoids).