Final answer:
MPF or Maturation Promoting Factor triggers the entry of cells into mitosis by phosphorylating various proteins, leading to chromatin condensation, nuclear envelope breakdown, spindle fiber formation, activation of separase, and ultimately cell division.
Step-by-step explanation:
MPF, also known as Maturation Promoting Factor or Mitosis Promoting Factor, triggers the entry of cells into mitosis. It does so by targeting numerous proteins within the cell, leading to a series of specific activities:
Phosphorylation of proteins that condense chromatin into chromatids.Breakdown of the nuclear envelope.Enabling of spindle fiber formation.Activation of enzymes like separase that allow chromatids to separate during anaphase.
MPF is composed of two subunits: cyclin, a regulatory polypeptide; and cyclin-dependent kinase (cdk), which contains the kinase enzyme active site. The activity of MPF peaks at mitosis after cyclin levels have gradually increased post-cytokinesis.
The phosphorylation cascade initiated by MPF can lead to a variety of cellular responses including the activation of transcription factors for gene regulation, and the initiation of processes such as chromosomal separation and cell division.