Cloning and Chromosomal Location of a Novel Member of the Myotonic Dystrophy Family of Protein Kinases

Yanming Zhao,Pascal Loyer,Haimin Li,Virginia Valentine,Vincent Kidd,Andrew S Kraft

doi:10.1074/jbc.272.15.10013

Abstract

We have cloned a novel serine/threonine protein kinase (PK428) which is highly related (65%) within the kinase domain to the myotonic dystrophy protein kinase (DM-PK), as well as the cyclic AMP-dependent protein kinase (33%). Northern blots demonstrate that PK428 mRNA is distributed widely among tissues and is expressed at the highest levels in pancreas, heart, and skeletal muscle, with lower levels in liver and lung. Two PK428 mRNAs 10 and 3.8 kilobase pairs in size are seen in a number of cell lines, including hematopoietic and breast cancer cells. An antibody generated to a glutathione S-transferase-PK428 fusion protein detects a 65-kDa protein in these cell lines, and a similarly sized protein when the cloned cDNA is transiently expressed in Cos 7 cells. Immunoprecipitation of the transiently expressed PK428 protein and incubation with [gamma-32P]ATP demonstrate that it is capable of autophosphorylation. In addition, immunoprecipitates of the PK428 protein kinase also phosphorylated histone H1 and a peptide encoding a cyclic AMP-dependent protein kinase substrate. The gene corresponding to the 3.8-kb PK428 mRNA, and its corresponding 65-kDa protein, was isolated by polymerase chain reaction screening of a P1 phage human genomic library. Using this P1 phage clone as a probe, the PK428 gene was located on 1q41-42, a possible location for a human senescence gene, a gene associated with Rippling muscle disease, as well as a region associated with genetically acquired mental retardation.

Highlights

We have cloned a novel serine/threonine protein kinase (PK428) which is highly related (65%) within the kinase domain to the myotonic dystrophy protein kinase (DM-PK), as well as the cyclic AMP-dependent protein kinase (33%)
Using fluorescence in situ hybridization (FISH) of the PK428 P1 phage clones, we found that the PK428 gene encoding the 3.8-kb mRNA and 65-kDa protein localizes to the long arm of human chromosome 1, the q41– 42 region
This 54-amino acid intracytoplasmic domain of the granulocyte-macrophage colony-simulating factor (GM-CSF) ␣ subunit appears to play an important role in signal transduction, the proteins that bind to this domain remain unknown [12, 13]

Summary

Introduction

We have cloned a novel serine/threonine protein kinase (PK428) which is highly related (65%) within the kinase domain to the myotonic dystrophy protein kinase (DM-PK), as well as the cyclic AMP-dependent protein kinase (33%). Consistent with the systemic nature of this disease, transcripts of the gene are expressed in various tissues, including the heart, skeletal muscle, liver, and brain, both in human and mouse [6, 7]. Another protein kinase related to the DM-PK, p160ROCK, has been shown to bind the small GTP-binding protein Rho, and it contains a protein kinase domain that shares 44% similarity to the DM-PK, an amphipathic ␣-helix, a pleckstrin domain, and a cysteine-rich region (8 –10). Deletion of the warts gene in Drosophila leads to the formation of cell clones that are fragmented, rounded, and greatly overgrown [11]

Methods

Results

Conclusion