Cell Division

Friday, August 26th 2005

So there is this cell just chugging along when the number of small peptide growth factors binding to some of it’s receptor integral proteins reaches some threshold and the second messenger system inside eventually causes the expression of a proto-onco gene whose product causes, among other things, the expression of a gene that produces cyclin.

Cyclin is involved in activation the cdc 2+/cdc 28 kinase on the Maturation Promoting Factor (MPF). MPF has three major functions in cell division: it signals the phosphorylation of the nuclear lamina intermediate filaments which breaks down the nuclear membrane, it condenses the DNA, and it helps in the creation of the spindle apparatus.