Ubiquitin, HSP40, HSP70, and the 20S proteasome colocalize with inclusions. Colocalization was determined by using confocal image analysis. SH-SY5Y cells were transfected with EGFP-HDQ74. In a, c, e, and g, the cells were microphotographed by using the FITC filter to show the inclusions formed by HD exon 1 constructs. In b, d, f, and h, the same cells are shown by using the Texas red filter to detect the other proteins sequestered into the inclusions. Cells were analyzed with specific antibodies: (a and b) anti-ubiquitin; (c and d) anti-HSP40 (HDJ-2/HSDJ); (e and f) anti-HSP70; (g and h) anti-20S proteasome.