BIOPHYSICS. For the article “Probing protein oligomerization in living cells with fluorescence fluctuation spectroscopy,” by Yan Chen, Li-Na Wei, and Joachim D. Müller, which appeared in issue 26, December 23, 2003, of Proc. Natl. Acad. Sci. USA (100, 15492-15497; first published December 12, 2003; 10.1073/pnas.2533045100), the authors note that the following acknowledgment was omitted from the article: “L.-N.W. acknowledges support from the National Institutes of Health (Grants DK54733, DK60521, and DA13926). Also, we thank Dr. Mariya Farooqui for her technical expertise and help with the Western blot.”