Figure 3. Patterns of protein distribution in HeLa cells.

Cyt. Cont is a control for cytosolic proteins obtained with the 0.3% Chaps buffer cell lysis (far left panel of bands) for the CDS method; Nuc. Cont is a control for nuclear proteins obtained with the classical method of nuclei isolation in hypotonic buffer (far right panel of bands) for the CDS method. (A) Proteins of cytosol: proteins extracted by regular lysis buffer and Buffer A from the cytoplasm. They are not detected in the perinuclear and the nuclear fractions. Nuclear fractions were obtained with new and classical nuclei extraction techniques (B) Proteins detected in the cytosol and the perinuclear fraction: proteins were detected as cytosolic proteins with both cellular lysis technique; in addition, these proteins also appeared in the perinuclear fraction by extraction with Buffer B. (C) Proteins of perinuclear fraction: proteins are detected only in perinuclear fraction by buffer B extraction. p53 protein was detected with long exposure. (D) Proteins detected in the nuclear and the perinuclear fractions: transcription factor CREB appeared in both fractions. (E) Nuclear proteins: proteins were detected in nuclear fraction. Nuclear proteins were obtained with new and classical nuclei isolation techniques. The PVDF membranes were cropped into two halves and the high and low molecular weight proteins were shown correspondingly.