Dual Specificity Phosphatase 5, a Specific Negative Regulator of ERK Signaling, Is Induced by Serum Response Factor and Elk-1 Transcription Factor

Abstract

Serum stimulation of mammalian cells induces, via the MAPK pathway, the nuclear protein DUSP5 (dual-specificity phosphatase 5), which specifically interacts with and inactivates the ERK1/2 MAP kinases. However, molecular mechanisms underlying DUSP5 induction are not well known. Here, we found that the DUSP5 mRNA induction depends on a transcriptional regulation by the MAPK pathway, without any modification of the mRNA stability. Two contiguous CArG boxes that bind serum response factor (SRF) were found in a 1 Kb promoter region, as well as several E twenty-six transcription factor family binding sites (EBS). These sites potentially bind Elk-1, a transcription factor activated by ERK1/2. Using wild type or mutated DUSP5 promoter reporters, we demonstrated that SRF plays a crucial role in serum induction of DUSP5 promoter activity, the proximal CArG box being important for SRF binding in vitro and in living cells. Moreover, in vitro and in vivo binding data of Elk-1 to the same promoter region further demonstrate a role for Elk-1 in the transcriptional regulation of DUSP5. SRF and Elk-1 form a ternary complex (Elk-1-SRF-DNA) on DUSP5 promoter, consequently providing a link to an important negative feedback tightly regulating phosphorylated ERK levels.

Dual-specificity phosphatase 5 controls the localized inhibition, propagation, and transforming potential of ERK signaling

“…We demonstrate that DUSP5, a phosphatase that is induced by ERK activity and specifically inactivates and anchors ERK in the nucleus (19)(20)(21)(22), can also increase cytoplasmic ERK activation (Fig. 1).…”

“…DUSP5, a nuclear-localized member of the MKP/DUSP family, is induced in response to ERK activation (19,20) and specifically dephosphorylates and anchors ERK in the nucleus (21). We recently established that Dusp5 knockout (KO) mice are sensitized to HRAS Q61L -driven DMBA/TPA (7,12-dimethylbenz[a] anthracene/12-O-tetra-decanoylphorbol-13-acetate)-initiated skin carcinogenesis, due to increased nuclear ERK activity and ERK-dependent SerpinB2 expression (22).…”

“…We therefore hypothesized that the propagation of cytoplasmic p-ERK levels ( Fig. 1 A and B) may arise because DUSP5 is induced by ERK activity (19,20). To test this prediction, we rescued DUSP5 expression in Dusp5 KO MEFs using adenovirus (Ad) vectors containing an ERK-responsive 1.2-kb EGR1 immediate early gene promoter to drive DUSP5-Myc expression (22).…”

“…We therefore modeled the relationship between ERK* and K* as highly cooperative by using a Hill function with a Hill coefficient of 4 (Table S1; SI Materials and Methods). Because ERK activation induces DUSP5 expression (19,20), we modeled DUSP5 synthesis as dependent upon ERK*, but with a delay to replicate the time lag incurred by transcription and translation. Because DUSP5 differentially controls nuclear and cytoplasmic ERK activity (Fig.…”

SRF Co-factors Control the Balance between Cell Proliferation and Contractility

“…Strikingly, TKO MEFs were significantly less proliferative than wild-type MEFs (Figure S1B), with increased numbers of cells in G2/M compared with wild-type cells (Figure S1C). They also exhibited somewhat enhanced ERK activation in response to TPA (Figure S1D), probably reflecting aberrant expression of ERK phosphatases (Buffet et al., 2015). Nevertheless, TPA induction of classical TCF-linked immediate-early genes was effectively abolished in TKO MEFs (Figure S1E), although serum induction of SRF target genes was less impaired (Figures S1A, S1E, and S1F).…”