Cyclin/cdk2 complexes in the nucleus of HeLa cells

Biochem Biophys Res Commun. 1994 Sep 30;203(3):1527-34. doi: 10.1006/bbrc.1994.2359.


Two different fractions of cdk2 and cdc2 have been found in the nucleus of HeLa cells. One, which can be extracted by nuclease treatment, possibly associated with DNA- or RNA-containing structures and another one, which is bound to the nuclear matrix. Nuclear cdk2 forms high molecular weight complexes which migrate at the same position as DNA polymerase alpha and proliferating cell nuclear antigen in sucrose gradient centrifugation experiments. These results suggest that nuclear cdk2 complexes could be associated with the replication factories. Immunoprecipitation experiments reveal that nuclear cdk2 complexes display histone H1-kinase activity and phosphorylate a protein of 18 kDa which is present in these complexes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Blotting, Western
  • CDC2-CDC28 Kinases*
  • Cell Fractionation
  • Cell Nucleus / chemistry
  • Cell Nucleus / metabolism*
  • Centrifugation, Density Gradient
  • Cyclin-Dependent Kinase 2
  • Cyclin-Dependent Kinases*
  • Cyclins / analysis
  • Cyclins / metabolism*
  • HeLa Cells
  • Humans
  • Nuclear Proteins / isolation & purification
  • Nuclear Proteins / metabolism
  • Protamine Kinase / analysis
  • Protamine Kinase / metabolism*
  • Protein-Serine-Threonine Kinases / analysis
  • Protein-Serine-Threonine Kinases / metabolism*


  • Cyclins
  • Nuclear Proteins
  • Protamine Kinase
  • Protein-Serine-Threonine Kinases
  • CDC2-CDC28 Kinases
  • CDK2 protein, human
  • Cyclin-Dependent Kinase 2
  • Cyclin-Dependent Kinases