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RGS6 interacts with DMAP1 and DNMT1 and inhibits DMAP1 transcriptional repressor activity
Journal article   Open access   Peer reviewed

RGS6 interacts with DMAP1 and DNMT1 and inhibits DMAP1 transcriptional repressor activity

Zhengyu Liu and Rory A Fisher
The Journal of biological chemistry, Vol.279(14), pp.14120-14128
04/02/2004
DOI: 10.1074/jbc.M309547200
PMID: 14734556
url
https://doi.org/10.1074/jbc.M309547200View
Published (Version of record) Open Access

Abstract

RGS6 is a member of a subfamily of mammalian RGS proteins that possess DEP (disheveled, Egl-10, pleckstrin) and GGL (G protein gamma subunit-like) domains in addition to the hallmark RGS domain. RGS proteins negatively regulate heterotrimeric G protein signaling by virtue of the GTPase-activating protein activity of their RGS domains. RGS6 exists in multiple splice forms with a long (6L) or short (6S) N terminus, a complete or incomplete GGL domain, in combination with various C-terminal domains. Green fluorescent protein-tagged RGS6L and RGS6S forms exhibit predominantly cytoplasmic and nuclear patterns of distribution in COS-7 cells, respectively, and traffic from these sites to nucleoli in response to stress signaling. We undertook a yeast two-hybrid screen for nuclear RGS6-binding proteins and here identify DMAP1 as an RGS6-interacting protein. DMAP1 is a component of the Dnmt1 complex involved in repression of newly replicated genes. The domains of interaction were mapped to the N-terminal region of the GGL domain of RGS6, a region distinct from its Gbeta5 binding region, and the C-terminal domain of DMAP1. Gbeta5 and DMAP1 did not compete for each other's interaction with RGS6. Co-immunoprecipitation studies in COS-7 cells showed that RGS6L and RGS6S, but not RGS6LDelta258-293 deletion mutant lacking a DMAP1-binding module, co-immunoprecipitate DMAP1 as well as Dnmt1 in a DMAP1-dependent manner. A recombinant GGL domain of RGS6 precipitated endogenous DMAP1 and Dnmt1 in neuroblastoma cell lysates and endogenous DMAP1 co-immunoprecipitated with RGS6L from mouse brain. Co-expression of DMAP1 with RGS6L promoted nuclear migration of RGS6L and its co-localization with DMAP1, a response not observed with RGS6LDelta258-293. RGS6 inhibited the transcriptional repressor activity of DMAP1. RGS6 is the first member of the RGS protein family shown to interact with proteins involved in transcriptional regulation.
Protein Structure, Tertiary RGS Proteins - genetics Repressor Proteins - chemistry DNA (Cytosine-5-)-Methyltransferase 1 Humans Gene Expression Regulation - physiology Repressor Proteins - genetics DNA (Cytosine-5-)-Methyltransferases - chemistry DNA (Cytosine-5-)-Methyltransferases - metabolism DNA (Cytosine-5-)-Methyltransferases - genetics Transcription, Genetic - physiology Animals RGS Proteins - chemistry Cell Line, Tumor Protein Binding RGS Proteins - metabolism COS Cells Repressor Proteins - metabolism

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