VWF is a Long, Thin Protein (image) Rice University Caption Von Willebrand factor (VWF) (green) is a long, thin protein that promotes blood clot formation. One end of VWF stays anchored to the blood vessel wall, while the rest unfurls like a sticky streamer, attracting platelets. Credit Nancy Turner/Rice University Usage Restrictions For news reporting purposes only. 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.