PMCA and SAAF Cell Signalling Pathway (IMAGE) University of Tokyo Caption This figure depicts how University of Tokyo researchers believe sperm cells navigate thanks to PMCA (plasma membrane Ca2+ ATPase) and SAAF (sperm activating and attracting factor). Credit ©2018 Manabu Yoshida, The University of Tokyo Usage Restrictions ©2018 Manabu Yoshida, The University of Tokyo License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.