We have identified previously a new murine protein serine/threonine kinase, MPK38, closely related to the sucrose-non-fermenting protein kinase family [Gil, Yang, Lee, Choi and Ha (1997) Gene 195, 295–301]. Using the C-terminal half of the putative human counterpart of MPK38, HPK38, as a bait in a yeast two-hybrid screen of a human HeLa cDNA library, it was discovered that the zinc-finger-motif-containing protein, termed zinc-finger-like protein 9 (ZPR9), bound both HPK38 and MPK38. In a co-expression assay, ZPR9 associated with MPK38 in vivo, and we showed that the ZPR9 is also phosphorylated by MPK38. In addition, ZPR9 physically interacts with itself in mammalian cells. The ZPR9 cDNA hybridized with a mRNA species of approx. 1.7kb in Northern-blot analysis. The ZPR9 transcript was detected in all tissues examined, including lung, kidney, spleen, liver and brain. Co-expression of ZPR9 with MPK38 caused the accumulation of ZPR9 in the nucleus. These findings suggest a potentially important role for ZPR9 in MPK38-mediated signal transduction, and that ZPR9 is a physiological substrate of MPK38 in vivo.
Abbreviations used: GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GFP, green fluorescent protein; GST, glutathione S-transferase; HPK38, human protein kinase 38; IL, interleukin; MPK38, murine protein kinase 38; MCAT, N-terminal catalytic domain of MPK38; SNF1, sucrose-non-fermenting protein kinase; ZF1, zinc-finger motif-1; ZPR9, zinc-finger-like protein 9.
Present address: Department of Pathology, Seoul National University Medical School, Yeongun-dong, Seoul 110-799, Korea.
The nucleotide sequence data reported will appear in GenBank® Nucleotide Sequence Database under the accession number AY046059.