Trihydrophobin 1 Is a New Negative Regulator of A-Raf Kinase

Liu, Weicheng; Shen, Xıaoyun; Yang, Yanzhong; Yin, Xiaomao; Xie, Jianhui; Yan, Jun; Jiang, Jianhai; Liu, Wenjing; Wang, Hanzhou; Sun, Maoyun; Zheng, Ying; Gu, Jianxin

doi:10.1074/jbc.m307994200

Cited by 20 publications

(32 citation statements)

References 64 publications

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“…NELF-C/ TH1L is a component of negative elongation factor (NELF) that is involved in promoterproximal pausing by RNA polymerase II [23]. Also, NELF-C/TH1L negatively regulates protein kinase A-raf [24]. In this context, the interaction MYST1-NELF-C may link acetylation of H4 K16 to diverse processes including regulation of transcription elongation and A-raf signaling.…”

Section: Discussionmentioning

confidence: 99%

Characterization of hampin/MSL1 as a node in the nuclear interactome

Dmitriev

Korneenko

Бессонов

et al. 2007

Biochemical and Biophysical Research Communications

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Hampin, homolog of drosophila MSL1, is a partner of histone acetyltransferase MYST1/MOF. Functions of these proteins remain poorly understood beyond their participation in chromatin remodeling complex MSL. In order to identify new proteins interacting with hampin, we screened a mouse cDNA library in yeast two-hybrid system with mouse hampin as bait and found five highconfidence interactors: MYST1, TPR proteins TTC4 and KIAA0103, NOP17 (homolog of a yeast nucleolar protein) and transcription factor GC BP. Subsequently, all these proteins were used as baits in library screenings and more new interactions were found: tumor suppressor RASSF1C and spliceosome component PRP3 for KIAA0103, ring finger RNF10 for RASSF1C, and RNA polymerase II regulator NELF-C for MYST1. The majority of the observed interactions was confirmed in vitro by pull-down of bacterially expressed proteins. Reconstruction of a fragment of mammalian interactome suggests that hampin may be linked to diverse regulatory processes in the nucleus.

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Section: Discussionmentioning

confidence: 99%

Characterization of hampin/MSL1 as a node in the nuclear interactome

Dmitriev

Korneenko

Бессонов

et al. 2007

Biochemical and Biophysical Research Communications

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“…Plasmids-Full-length TH1 expression plasmids were constructed as described previously (31). Myc-PAK1 WT, Myc-PAK1 T423E, and Myc-PAK1 K299R (provided by J. Chernoff) were amplified by PCR and cloned into the SalI/BamHI site of pEGFP-N3 vector or the SacI/BamHI site of pDsRed-Express-C1 vector (Clontech).…”

Section: Methodsmentioning

confidence: 99%

“…Although highly conserved and ubiquitously expressed, human TH1 is not well understood in terms of its function. Recently, data from our laboratory indicate that TH1, as a new negative regulator of A-RAF kinase in MAPK signal transduction pathways, can specifically bind to A-RAF and inhibit its kinase activity (31). TH1 also interacts with human papilloma virus E6-associated protein (E6AP) and induces ubiquitin-dependent proteolysis (32).…”

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confidence: 99%

Trihydrophobin 1 Interacts with PAK1 and Regulates ERK/MAPK Activation and Cell Migration

Cheng

Kong

Wang

et al. 2009

Journal of Biological Chemistry

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The Rac1/Cdc42 effector, p21-activated kinase (PAK), is activated by various signaling cascades, including receptor-tyrosine kinases and integrins, and regulates a number of processes such as cell proliferation and motility. PAK activity has been shown to be required for maximal activation of the canonical RAF-MEK-MAPK signaling cascade, possibly because of PAK co-activation of RAF and MEK. Here we have shown that trihydrophobin 1 (TH1), originally identified as a negative regulator of A-RAF kinase, also interacted with PAK1 in cultured cells. Confocal microscopy assay indicated that TH1 colocalized with PAK1 in both the cytoplasm and nucleus, which is consistent with our previous results. GST pulldown and coimmunoprecipitation experiments demonstrated that TH1 interacted directly with PAK1 and bound selectively to the carboxyl-terminal kinase domain of PAK1, and the ability of the binding was enhanced along with activation of PAK1. The binding pattern of PAK1 implies that this interaction was mediated in part by PAK1 kinase activity. As indicated by in vitro kinase activity assays and Western blot detections, TH1 inhibited PAK1 kinase activity and negatively regulated MAPK signal transduction. Interestingly, TH1 bound with MEK1/ERK in cells and in vitro without directly suppressing their kinase activity. Furthermore, we observed that TH1 localized to focal adhesions and filopodia in the leading edge of cells, where TH1 reduced cell migration through affecting actin and adhesion dynamics. Based on these observations, we propose a model in which TH1 interacts with PAK1 and specifically restricts the activation of MAPK modules through the upstream region of the MAPK pathway, thereby influencing cell migration.

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“…During the course of our project new data have been reported in relation with the mammalian homologues of DDB0232149 and DDB0232141. DDB0232149 shows similarity to the Pfam domain TH1 that is present in a group of highly conserved metazoan proteins and has been shown to function as a negative regulator of A-Raf kinase (Liu et al, 2004). However, the human homologue to DDB0232141, UFC1, is a new component of an ubiquitin-like (UBL) post-translational modifiers (Komatsu et al, 2004).…”

Section: Knockout Analysis Of Genes Of Unknown Function In Dictyosteliummentioning

confidence: 99%

Functional genomics inDictyostelium: MidA, a new conserved protein, is required for mitochondrial function and development

Torija

Vicente

Rodrigues

et al. 2006

Journal of Cell Science

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Genomic sequencing has revealed a large number of evolutionary conserved genes of unknown function. In the absence of characterized functional domains, the discovery of the role of these genes must rely on experimental approaches. We have selected 30 Dictyostelium discoideum genes of unknown function that showed high similarity to uncharacterized human genes and were absent in the complete proteomes from Saccharomyces cerevisiae and S. pombe. No putative functional motifs were found in their predicted encoded proteins. Eighteen genes were successfully knocked-out and three of them showed obvious phenotypes. A detailed analysis of one of them, midA, is presented in this report. Disruption of midA in Dictyostelium leads to pleiotropic defects. Cell size, growth rate, phagocytosis and macropinocytosis were affected in the mutant. During development, midA- cells showed an enhanced tendency to remain at the slug stage, and spore viability was compromised. The expression of MidA fused to GFP in midA- strain rescued the phenotype and the fused protein was located in the mitochondria. Although cellular oxygen consumption, mitochondrial content and mitochondrial membrane potential were similar to wild type, the amount of ATP was significantly reduced in the mutant suggesting a mitochondrial dysfunction. Metabolomic analysis by natural-abundance 13C-nuclear magnetic resonance has shown the lack of glycogen accumulation during growth. During starvation, mutant cells accumulated higher levels of ammonia, which inhibited normal development. We hypothesize that the lack of MidA reduces mitochondrial ATP synthetic capacity and this has an impact in some but not all energy-dependent cellular processes. This work exemplifies the potential of Dictyostelium as a model system for functional genomic studies.

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Trihydrophobin 1 Is a New Negative Regulator of A-Raf Kinase

Cited by 20 publications

References 64 publications

Characterization of hampin/MSL1 as a node in the nuclear interactome

Characterization of hampin/MSL1 as a node in the nuclear interactome

Trihydrophobin 1 Interacts with PAK1 and Regulates ERK/MAPK Activation and Cell Migration

Functional genomics inDictyostelium: MidA, a new conserved protein, is required for mitochondrial function and development

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