C. ABCA1 (IMAGE) Penn State Caption C. ABCA1 was postulated either to be the scramblase shown in B or to enhance its activity in moving PS to the cell surface. This hypothesis is not supported by the evidence in this study. Therefore, ABCA1 must act in loading the lipids and cholesterol onto the apoA1 molecule generating an HDL particle. Credit PSU Usage Restrictions None 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.