Giant clams display light-enhanced inorganic phosphate (P i ) absorption, but how the absorbed P i is translocated to the symbiotic dinoflagellates living extracellularly in a tubular system is unknown. They can accumulate P i in the kidney, but the transport mechanism remains enigmatic. This study aimed to elucidate the possible functions of sodium-dependent phosphate transporter protein 1-homolog (PiT1-like), which co-transp...