Open AccessBiosynthesis of casein kinase II in lymphoid cell lines
Author(s) -
LÜSCHER Bernhard,
LITCHFIELD David W.
Publication year - 1994
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1994.tb18651.x
Subject(s) - biosynthesis , chemistry , microbiology and biotechnology , kinase , casein kinase 1 , casein kinase 2 , biochemistry , biology , protein kinase a , mitogen activated protein kinase kinase , gene
We have analyzed the biosynthesis of casein kinase II. In exponentially growing tissue culture cells, the β subunit was synthesized in excess of the catalytic subunit (α). A substantial fraction of newly synthesized β was degraded within the first hour. The remaining fraction of β was incorporated into holoenzyme. In contrast, little degradation of newly synthesized α subunit was observed and most was quickly and efficiently incorporated into holoenzyme. The assembly of β with α was paralleled by an increase in apparent molecular mass of β due to phosphorylation. The subcellular distribution of newly synthesized [ 35 S]Met‐labelled casein kinase II and of enzyme labelled and chased in the presence of excess unlabelled methionine was very similar and compatible with a nuclear localization. The degradation of the excess β subunit occurred through a non‐lysosomal proteolytic system with a very low ATP requirement.