Structure, mapping, and expression of erp, a growth factor-inducible gene encoding a nontransmembrane protein tyrosine phosphatase, and effect of ERP on cell growth.

Abstract

We have characterized a growth factor-inducible gene, erp, and demonstrated that it encodes a 367-aminoacid nontransmembrane tyrosine phosphatase protein with significant similarity to The proliferation of animal cells is initiated and regulated by growth factors. The interaction of growth factors with their specific receptors generates a cascade of intracellular biochemical signals leading to the expression of growth factor-regulated genes. Recent studies on the genetic basis of cell proliferation have shown that growth factors and mitogens are capable of rapidly inducing a complex set of genes, named the immediate-early genes, in fibroblasts. These genes are transcriptionally activated within minutes after growth factor or mitogen addition, independent of de novo protein synthesis (3,12,29). Some of these genes encode bona fide or putative transcription factors, including members of the Fos, Jun, Myc, Rel, and zinc finger family proteins, which are thought to act as "third messengers" in the cascade of events triggered by growth factors (5,7,22,30,40). The function of some of these proteins has been demonstrated to be essential for cell cycle progression and entry into the S phase (23,26,27,36). Further evidence that some of these proteins have a positive effect on cell growth is the observation that their deregulated expression can induce malignant cell transformation (28,31,34,37,42,43,50).We have previously reported the isolation of a set of cDNAs corresponding to serum-inducible immediate-early genes in mouse fibroblasts (3). In this report, we describe the characterization of one of these genes and show that it encodes a nontransmembrane protein tyrosine phosphatase. As RNA extraction and Northern (RNA blot) analysis. Total RNA was prepared from cells and tissues by the guanidine hydrochloride procedure (11). To obtain polyadenylated RNA, total RNA was dotted onto messenger-activated paper (Orgenics Ltd.), washed twice for 15 min each in PBS, and then washed with 70% ethanol for 10 min. After the messenger-activated paper was dried, the polyadenylated RNA was released by incubation in water at 70°C for 5 min. For Northern blot analysis, RNA was separated in 1% agarose gels containing 6% formaldehyde (46) and blotted onto a GeneScreen Plus membrane (NEN-DuPont). The purified insert of the original erp clone, X97 (3), was labeled by random-primer labeling (16,17) to a specific activity of 1 x 109 to 4 x 109 cpm/,ug. The hybridization was carried out in 50% formamide-0.5% sodium dodecyl sulfate (SDS)-5 x 5195

Essential role of calcium in the regulation of MAP kinase phosphatase-1 expression

“…The in¯ux of Ca 2+ through voltage-sensitive Ca 2+ channels also stimulates serum response factor (SRF)-dependent transcription in the pheochromocytoma cell line PC12 (Miranti et al, 1995). Sequencing of the 5'¯anking region of the mouse MKP-1 gene revealed the presence of several consensus sequences that include one CRE, two SP1 sites, two CTF/NF1-like sites, and one E-box motif (Noguchi et al, 1993). The human MKP-1 gene is alsō anked by two CREs (Kwak et al, 1994).…”

“…All these enzymes bear the characteristic active-site motif of protein tyrosine phosphatases (PTPs) and display sequence homology to the vaccinia virus VH1 phosphatase (Guan et al, 1991). The ®rst mammalian gene of this family to be discovered was mouse 3CH134 (also known as erp) and its human homologue CL100 (also known as hVH-1) which was isolated as an immediate-early gene inducible by growth factors and stress (Charles et al, 1992;Keyse and Emslie, 1992;Noguchi et al, 1993;Zheng and Guan, 1993). Recombinant 3CH134/CL100 puri®ed from bacteria preferentially dephosphorylates the phosphothreonine and phosphotyrosine residues of MAP kinases in vitro resulting in their inactivation Alessi et al, 1993;Zheng and Guan, 1993).…”

“…On the basis of these results, the 3CH134/CL100 phosphatase was renamed MAP kinase phosphatase-1 (MKP-1). The expression of MKP-1 was further shown to inhibit ERK-dependent reporter gene activity (Sun et al, 1994b;Brondello et al, 1995), to block cell cycle progression and entry into S phase of ®broblast cells (Noguchi et al, 1993;Sun et al, 1994b;Brondello et al, 1995) and to prevent PC12 cell di erentiation (Fukuda et al, 1995). All these observations suggest that MKP-1 might be a physiological MAP kinase phosphatase, but its relative contribution to the inactivation of MAP kinases in speci®c cellular processes in vivo remains to be established.…”

“…The induction of MKP-1 mRNA expression has been observed in several cell types in response to stimuli as diverse as growth and di erentiation factors, cAMP-elevating agents, phorbol esters, heat shock, oxidative stress, and genotoxic agents (Charles et al, 1992;Keyse and Emslie, 1992;Noguchi et al, 1993;Du et al, 1993;Liu et al, 1995). The aim of this study was to characterize the signalling pathways involved in the regulation of MKP-1 expression.…”

CREB and AP‐1 activation regulates MKP‐1 induction by LPS or M‐CSF and their kinetics correlate with macrophage activation versus proliferation

“…To determine the regulatory areas of the MKP-1 promoter, we cloned a 650-bp fragment upstream of the initial ATG [41] and included it in a vector containing luciferase as the reporter enzyme. This plasmid was transfected into macrophages, which were rendered quiescent for 16-18 h and subsequently treated with M-CSF or LPS.…”