To establish if, in addition to CFTR, the CFTR partner protein NHERF-1, known to undergo digestion by calpain in CF-PBMC [10], is also recovered in CI-2-treated cells, the levels of the native 50 kD and the calpain-digested 20 kD NHERF-1 forms were comparatively analyzed in control and CF-PBMC. Here, CFTR is linked to cystic fibrosis.