Effect of 4-HAP (IMAGE) Johns Hopkins Medicine Caption Treating cells with 4-HAP causes the protein myosin II to move to the cells' periphery, making them stiffer. Credit Alexandra Surcel/Johns Hopkins Medicine Usage Restrictions Credit required 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.