TY - JOUR
T1 - Specific interaction between casein kinase 2 and the nucleolar protein Nopp140
AU - Li, Dongxia
AU - Thomas Meier, U.
AU - Dobrowolska, Grazyna
AU - Krebs, Edwin G.
PY - 1997
Y1 - 1997
N2 - Casein kinase 2 (CK2) is a multifunctional second messenger-independent protein serine/threonine kinase that phosphorylates many different proteins. To understand the function and regulation of this enzyme, biochemical methods were used to search for CK2-interacting proteins. Using immobilized glutathione S-transferase fusion proteins of CK2, the nucleolar protein Nopp140 was identified as a CK2-associated protein. It was found that Nopp140 binds primarily to the CK2 regulatory subunit, β. The possible in vivo association of Nopp140 with CK2 was also suggested from a coimmunoprecipitation experiment in which Nopp140 was detected in immunoprecipitates of CK2 prepared from cell extracts. Further studies using an overlay technique with radiolabeled CK2 as a probe revealed a direct CK2- Nopp140 interaction. Using deletion mutants of CK2β subunits, the binding region of the CK2β subunit to Nopp140 has been mapped. It was found that the NH2-terminal 20 amino acids of CK2β are involved. Since Nopp140 has been identified as a nuclear localization sequence-binding protein and has been shown to shuttle between the cytoplasm and the nucleus, the finding of a CK2- Nopp140 interaction could shed light on our understanding of the function and regulation of CK2 and Nopp140.
AB - Casein kinase 2 (CK2) is a multifunctional second messenger-independent protein serine/threonine kinase that phosphorylates many different proteins. To understand the function and regulation of this enzyme, biochemical methods were used to search for CK2-interacting proteins. Using immobilized glutathione S-transferase fusion proteins of CK2, the nucleolar protein Nopp140 was identified as a CK2-associated protein. It was found that Nopp140 binds primarily to the CK2 regulatory subunit, β. The possible in vivo association of Nopp140 with CK2 was also suggested from a coimmunoprecipitation experiment in which Nopp140 was detected in immunoprecipitates of CK2 prepared from cell extracts. Further studies using an overlay technique with radiolabeled CK2 as a probe revealed a direct CK2- Nopp140 interaction. Using deletion mutants of CK2β subunits, the binding region of the CK2β subunit to Nopp140 has been mapped. It was found that the NH2-terminal 20 amino acids of CK2β are involved. Since Nopp140 has been identified as a nuclear localization sequence-binding protein and has been shown to shuttle between the cytoplasm and the nucleus, the finding of a CK2- Nopp140 interaction could shed light on our understanding of the function and regulation of CK2 and Nopp140.
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U2 - 10.1074/jbc.272.6.3773
DO - 10.1074/jbc.272.6.3773
M3 - Article
C2 - 9013635
AN - SCOPUS:0031013280
SN - 0021-9258
VL - 272
SP - 3773
EP - 3779
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 6
ER -