When CDK activity is low= helicases are loaded in G1

When CDK activity is high= helicases are activated in

S, G2 & M

TLS Online TPP Program

#Id: 8880

#Section 3: Genetics, Cellular and Molecular Biology

Active cytoplasmic cyclin B-CDK1 translocates into the nucleus, where it phosphorylates nuclear lamins to cause nuclear envelope breakdown and, together with Plk1 and the Aurora kinases, induces chromosome condensation and formation of the mitotic spindle.

TLS Online TPP Program

#Id: 8881

#Section 3: Genetics, Cellular and Molecular Biology

Plk1 is critical for formation of the mitotic spindle as well as for chromosome segregation.

TLS Online TPP Program

#Id: 8882

#Section 3: Genetics, Cellular and Molecular Biology

The Aurora kinase family members Aurora A and Aurora B play key roles in mitotic spindle formation and in ensuring that chromosomes attach correctly to the mitotic spindle so that they are segregated accurately during mitosis.

TLS Online TPP Program

#Id: 8883

#Section 3: Genetics, Cellular and Molecular Biology

Once mitotic CDKs are activated at the end of G2 , they phosphorylate specific serine residues in all 3 nuclear lamins.

TLS Online TPP Program

#Id: 8884

#Section 3: Genetics, Cellular and Molecular Biology

This phosphorylation, together with phosphorylation of lamin B by protein kinase C, causes depolymerization of the lamin intermediate filaments.

TLS Online TPP Program

#Id: 8885

#Section 3: Genetics, Cellular and Molecular Biology