Analysis of phosphorylated isoforms of the p53 tumor suppressor protein in human lung carcinoma cells undergoing apoptosis.
The expression of p53 tumor suppressor protein isoforms in H460a cells induced to undergo apoptosis by 2-methoxyestradiol was investigated by two-dimensional gel electrophoresis. Whole-cell proteins from control and apoptotic H460a cells were separated by two-dimensional electrophoresis and were transferred to nitrocellulose. The p53 isoforms were detected by immunoblotting using p53 monoclonal antibody Bp53-12. Four isoforms of p53 (2, 3, 5, and 6) differing in phosphorylation state were detected in control cells. Three additional isoforms (1, 4, and 7) were observed to be expressed at significant levels only in apoptotic cells. The differential expression of isoforms 1, 4, and 7 in apoptotic cells suggests that one or more specific phosphorylation events generating these forms of p53 could play a role in regulating the function of p53 in apoptosis.
Maxwell
S A
SA
Department of Pathology, Texas A&M Health Science Center, College Station 77843-1114, USA. s-maxwell@tamu.edu
Roth
J A
JA
Mukhopadhyay
T
T
D000077584:2-Methoxyestradiol; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D053938:DNA Fragmentation; D015180:Electrophoresis, Gel, Two-Dimensional; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D009363:Neoplasm Proteins / Q000302:isolation & purification* / Q000378:metabolism; D010750:Phosphoproteins / Q000302:isolation & purification* / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D014407:Tumor Cells, Cultured / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000302:isolation & purification* / Q000378:metabolism
D009363:Neoplasm Proteins; D010750:Phosphoproteins; D016159:Tumor Suppressor Protein p53; D004958:Estradiol; D000077584:2-Methoxyestradiol