Light-harvesting photosynthetic bile pigment-protein from the phycobiliprotein complex (phycobilisome, PBS). Phycocyanin is the major phycobiliprotein in the PBS rod. Heterodimer of an alpha and a beta subunit (PubMed:16920511). The hererodimer further assembles into trimers and the trimers into hexamers (By similarity). Part of the phycobilisome rod. Contains two covalently linked bilin chromophores. Spirulina fusiformis, is used as a source of protein and vitamin supplement in drinks. In cell culture induces a urokinase-type plasminogen activator; may therefore be useful in dissolving blood clots. Belongs to the phycobiliprotein family.