Salk beta cells image (IMAGE) Salk Institute Caption This image shows functional beta cells made from human pluripotent stem cells. Insulin (red) and NKX6.1 (green) indicate two proteins produced by beta cells. Credit Salk Institute Usage Restrictions with credit and related coverage. 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.