The Ki-67 protein interacts with members of the heterochromatin protein 1 (HP1) family: a potential role in the regulation of higher-order chromatin structure.
The expression of the nuclear protein Ki-67 (pKi-67) is strictly correlated with cell proliferation. Because of this, anti-Ki-67 antibodies can be used as operational markers to estimate the growth fraction of human neoplasia in situ. For a variety of tumours, the assessment of pKi-67 expression has repeatedly been proven to be of prognostic value for survival and tumour recurrence, but no cellular function has yet been ascribed to the Ki-67 protein. This study shows that a C-terminal domain of pKi-67 (Kon21) is able to bind to all three members of the mammalian heterochromatin protein 1 (HP1) family in vitro and in vivo. This interaction can be manipulated in living cells, as evidenced by ectopic expression of GFP-tagged HP1 proteins in HeLa cells, which results in a dramatic relocalization of endogenous pKi-67. Taken together, the data presented in this study suggest a role for pKi-67 in the control of higher-order chromatin structure.
Scholzen
Thomas
T
Division of Molecular Immunology, Research Center Borstel, D-23845 Borstel, Germany. tscholzen@fz-borstel.de
Endl
Elmar
E
Wohlenberg
Claudia
C
van der Sar
Sjaak
S
Cowell
Ian G
IG
Gerdes
Johannes
J
Singh
Prim B
PB
D000818:Animals; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000648:ultrastructure*; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D007399:Interphase; D019394:Ki-67 Antigen / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics; D020033:Protein Isoforms / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics; D014162:Transfection; D020798:Two-Hybrid System Techniques
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D019394:Ki-67 Antigen; D008164:Luminescent Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D000090266:Chromobox Protein Homolog 5; D049452:Green Fluorescent Proteins