Abstract
Protein phosphorylation and dephosphorylation has been recognized as a key mechanism in the regulation of cellular metabolism and functions in various tissues. Several lines of evidence indicate that protein phosphorylation is intimately related to cell proliferation and differentiation, including a biological end point, apoptosis. Apoptosis has been recognized to be of major importance for embryonic development, tissue homeostasis, neurodegeneration, autoimmune disease, carcinogenesis, cancer progression, and the killing of cancer cells by chemotherapeutic drugs. The characteristic morphological changes of apoptosis include cytoplasmic shrinkage, plasma membrane blebbing, chromatin condensation, and formation of apoptotic bodies containing well-preserved organelles. In addition, apoptotic cells undergo double strand cleavage of nuclear DNA at the linker regions between nucleosomes into fragments of multiples of about 185-200 bp resulting in a characteristic laddering pattern on agarose gel electrophoresis. In the present review, I demonstrate that the relationship between protein dephosphorylation and apoptotic processes in the cells including Saos-2 cells, MG63 cells, MC3T3-E1 cells, SCC-25 cells, SCCTF cells, SCCKN cells, HSG cells, and CHO cells studied in our laboratory.
