Identification by Targeted Differential Display of an Immediate Early Gene Encoding a Putative Serine/Threonine Kinase

doi:10.1074/jbc.270.17.10351

Identification by Targeted Differential Display of an Immediate Early Gene Encoding a Putative Serine/Threonine Kinase(*)

From the (1) Department of Molecular Biology, Holland Laboratory, American Red Cross, Rockville, Maryland 20855

^¶ To whom reprint requests and correspondence should be addressed:
Dept. of Molecular Biology, Holland Laboratory, American Red Cross, 15601 Crabbs Branch Way, Rockville, MD 20855.
Tel.: 301-738-0655; Fax: 301-738-0465.

↵^§ This work was performed in partial fulfillment of the requirements for the degree of Doctor of Philosophy from the Graduate Genetics Program, George Washington University, Washington, D.C. 20037. Present address: Laboratory of Biological Chemistry, National Cancer Inst., National Institutes of Health, Bethesda, MD 20892.

Abstract

Fibroblast growth factor (FGF)-1 mitogenic signal transduction is mediated in part by gene products that are specifically expressed in response to cell surface receptor binding and activation. We have used a targeted differential display method to identify FGF-1-inducible genes in murine NIH 3T3 fibroblasts. Here we report that one of these genes is predicted to encode a novel serine/threonine-specific protein kinase. This putative kinase has been named Fnk, for FGF-inducible kinase. The deduced Fnk amino acid sequence has 49, 36, 33, 32, and 22% overall identity to mouse serum-inducible kinase (Snk), mouse polo-like kinase (Plk), Drosophila polo, Saccharomyces Cdc5, and mouse Snk/Plk-akin kinase (Sak), respectively. These proteins are all members of the polo subfamily of structurally related serine/threonine kinases. The Plk, polo, Cdc5, and Sak kinases are required for cell division. FGF-1 induction of Fnk mRNA expression is first detected at 30 min after mitogen addition, reflects transcriptional activation, and does not require de novo protein synthesis. FGF-2, platelet-derived growth factor-BB, calf serum, or phorbol myristate acetate treatment of quiescent cells also induces fnk gene expression. Fnk mRNA is expressed in vivo in a tissue-specific manner, with relatively high levels detected in newborn and adult mouse skin. These results indicate that Fnk may be a transiently ex-pressed protein kinase involved in the early signaling events required for growth factor-stimulated cell cycle progression.

Footnotes

↵* This study was supported in part by National Institutes of Health Grant HL-39727 (J. A. W.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank/EMBL Data Bank with accession number(s) U21392 and U22434.
↵¹ The abbreviations used are:

FGF

fibroblast growth factor

bp

base pair(s)

EGF

epidermal growth factor

Fnk and fnk

FGF-inducible kinase

IGF

insulin-like growth factor

kb

kilobase(s)

PCR

polymerase chain reaction

PDGF

platelet-derived growth factor

Plk and plk

polo-like kinase

PMA

phorbol myristate acetate

Sak

Snk/Plk-akin kinase

sgk

serum- and glucocorticoid-regulated kinase

Snk and snk

serum-inducible kinase

TGF

transforming growth factor.
↵²P. J. Donohue and J. A. Winkles, manuscript in preparation.