Rod linker protein, associated with phycocyanin. Linker polypeptides determine the state of aggregation and the location of the disk-shaped phycobiliprotein units within the phycobilisome and modulate their spectroscopic properties in order to mediate a directed and optimal energy transfer. Part of 2 PBS rod complexes, the conventional CpcG-PBS rod and a photosystem I-specific CpcL-PBS rod, both of which include ferredoxin--NADP reductase (petH). CpcG-PBS has on average 3 stacked phycocyanin hexamers (PC, CpcA and CpcB). Linker CpcG connects the PC stack to the thylakoid, the hexamers are linked by 1 copy of CpcC1, 1 copy of CpcC2 and the stack is terminated by a single copy of CpcD. The CpcL-PBS has on average 5 stacked phycocyanin hexamers (PC, CpcA and CpcB). Linker CpcL connects the PC stack to the thylakoid, the hexamers are linked by 1 copy of CpcC1, 3 copies of CpcC2 and the stack is terminated by a single copy of CpcD (PubMed:31015331). Interacts with the C-phycocyanin (PC) beta subunit (cpcB), it may fit into the center of the PC hexamer (PubMed:21923764). This protein occurs in the rod, it is associated with phycocyanin. The N-terminal PBS-linker domain (residues 19-157 in this experiment) interacts with the C-phycocyanin beta subunit (cpcB). Belongs to the phycobilisome linker protein family.