Phosphorylation of Srplp, the yeast nuclear localization signal receptor, in vitro and in vivo

摘要

Srplp, the protein encoded by SRPl of the yeast Saccharomyces cerevisiae, is a yeast nuclear localization signal (NLS) receptor protein. We have previously reported isolation of a protein kinase from yeast extracts that phosphorylates Srplp complexed with NLS peptides/proteins. From partial amino acid sequences of the four subunits of the purified kinase, we have now identified this protein kinase to be identical to yeast casein kinase Ⅱ (CKII).