Proliferating cell nuclear antigen originally identified as an antigen that is expressed in the nuclei of cells during the DNA synthesis phase of the cell cycle. Part of the protein was sequenced and that sequence was used to allow isolation of a cDNA clone. PCNA helps hold DNA polymerase epsilon (Pol ε) to DNA. PCNA is clamped to DNA through the action of replication factor C (RFC), which is a heteropentameric member of the AAA+ class of ATPases. Expression of PCNA is under the control of E2F transcription factor-containing complexes. Since DNA polymerase epsilon is involved in resynthesis of excised damaged DNA strands during
Calcium signaling in cell division cell lines, that the G2/M checkpoint is regulated by CaMKII and MAPK crosstalk. Here, CaMKII activates MEK/ERK, which degrades the cell cycle arresting p27 protein In general, transformed cells proliferate in a calcium-independent manner, whereas non-transformed cells show high sensitivity to extra-cellular calcium concentration, suggesting oncogenic growth may include disruption of calcium signaling. Condensation of chromatin is a vital step in cell division, allowing cells to equally distribute chromosomes to the daughter cells. Recent work has suggested that Ca is required for enabling chromatin condensation in prometaphase. Calcium was found to concentrate on condensed DNA to much higher levels compared