Rabphilin-3A binds to a Mr 115,000 polypeptide in a phosphatidylserine- and Ca2+-dependent manner

Miyazaki, Mutsuo; Kaibuchi, Kozo; Shirataki, Hiromichi; Kohno, H.; Ueyama, Tomomi; Nishikawa, Junsuke; Takai, Yoshimi

doi:10.1016/0169-328x(94)00180-m

Cited by 19 publications

(9 citation statements)

References 31 publications

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“…It has been suggested that this C2 domain, which is also found in synaptotagmins, phospholipases A2 and C, GTPase-activating proteins, and rabphilin-3A, functions as a calcium binding site (72). In the case of rabphilin-3A, it was shown that the C2 domain specifically interacts with a 115-kDa protein in a calcium-and phosphatidylserine-dependent manner (50). At present, we have no experimental data to support the involvement of the potential C2 domain in the transcription potentiation function of either RSP5 or hRPF1.…”

Section: Discussionmentioning

confidence: 99%

Yeast RSP5 and Its Human Homolog hRPF1 Potentiate Hormone-Dependent Activation of Transcription by Human Progesterone and Glucocorticoid Receptors

Imhof

McDonnell

1996

Molecular and Cellular Biology

153

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We have developed a system in Saccharomyces cerevisiae in which agonist-dependent transcriptional activity of the human progesterone receptor (hPR) is elevated to the point that it compromises cell growth. Screens for suppressors of this phenotype led to the demonstration that RSP5 is involved in hPR transactivation. Expression of RSP5 in yeast cells potentiated hPR and human glucocorticoid receptor (hGR) transcriptional activity and increased the efficacy of weak agonists of these receptors. Remarkably, expression of this yeast protein in mammalian cells had a similar effect on PR and GR transcriptional activity. Importantly, a human homolog of RSP5, hRPF1, functioned identically in mammalian cells. Previously, it has been demonstrated that RSP5 overexpression in yeast cells suppressed mutations within SPT3, a protein which interacts with the TATAbox-binding protein (TBP), suggesting that RSP5 and SPT3 operate in the same regulatory pathway. In support of this observation, we have shown that SPT3 enhances the activity of RSP5 on GR and PR when tested in yeast or mammalian cells. We conclude from these experiments that the regulatory pathways in which RSP5 and SPT3 operate in yeast cells are conserved in higher eukaryotes. Additionally, since SPT3 has been shown to contact yeast TBP directly and is the likely homolog of human TBP-associated factor TAF II 18, we propose that RSP5/hRPF1 and SPT3 establish a functional link between activated PR and GR and the general transcription apparatus.Steroid hormone receptors are ligand-inducible transcription factors belonging to a superfamily of nuclear proteins (16, 17) which also includes receptors for vitamins and thyroid hormone as well as orphan receptors for which no ligands have yet been identified. Within this superfamily, the steroid receptors represent a subgroup of proteins which have considerable sequence similarity and are closely related mechanistically. In the absence of hormone, the steroid receptors are transcriptionally inert and reside in a large macromolecular docking complex consisting of heat shock protein 90 (hsp90), hsp70, hsp56, and other, less well characterized proteins. Upon interaction with their cognate ligands, they undergo a conformational change, displacing the associated heat shock proteins and spontaneously forming receptor homodimers. Subsequently, the homodimeric receptor complex can interact with high affinity with specific DNA response elements located within the regulatory regions of target genes. It is the ability to cooperate with additional cell specific transcription factors, or other trans-acting factors located on the same promoter, which determines the biological activity of the DNA-bound receptor (44, 51). The precise mechanism by which steroid receptors alter transcription by RNA polymerase II is unknown. However, it has been shown that transcriptionally active progesterone receptor (PR) can potentiate target gene transcription, in a reconstituted system in vitro, by stabilizing the preinitiation complex (34). Additionally, ...

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Section: Discussionmentioning

confidence: 99%

Yeast RSP5 and Its Human Homolog hRPF1 Potentiate Hormone-Dependent Activation of Transcription by Human Progesterone and Glucocorticoid Receptors

Imhof

McDonnell

1996

Molecular and Cellular Biology

153

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“…One possible speculative role of the Rab3A-rabphilin-3A system in the regulation of the reorganization of actin filaments is that the conversion of GTP-Rab3A to GDP-Rab3A by the action of Rab3 GTPase-activating protein and the subsequent dissociation of GDP-Rab3A from rabphilin-3A initiates the interaction of rabphilin-3A with ␣-actinin, eventually stimulating the bundling of actin filaments, which may be involved in the docking and fusion processes. We have shown previously that rabphilin-3A interacts with ␤-adducin through the C2-like domain in the presence of Ca 2ϩ and phospholipid (44,45). ␤-Adducin has been implicated in the assembly of spectrin-actin complexes (for a review, see Ref.…”

Section: Discussionmentioning

confidence: 99%

Physical and Functional Interaction of Rabphilin-3A with α-Actinin

Kato

Sasaki

Ohya

et al. 1996

Journal of Biological Chemistry

Self Cite

105

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Rabphilin-3A is a downstream target molecule of Rab3A small GTP-binding protein and implicated in Ca 2؉dependent neurotransmitter release. Here we have isolated a rabphilin-3A-interacting molecule from a human brain cDNA library by the yeast two-hybrid method and identified it to be ␣-actinin, known to cross-link actin filaments into a bundle. ␣-Actinin interacts with the N-terminal region of rabphilin-3A, with which GTPRab3A interacts, and this interaction stimulates the activity of ␣-actinin to cross-link actin filaments into a bundle. The interaction of rabphilin-3A with ␣-actinin is inhibited by guanosine 5-(3-O-thio)triphosphateRab3A. These results suggest that the Rab3A-rabphilin-3A system regulates the ␣-actinin-regulated reorganization of actin filaments. It has been shown that reorganization of actin filaments is also involved in Ca 2؉ -dependent exocytosis. Therefore, rabphilin-3A may serve as a linker for Rab3A and cytoskeleton.

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“…The C2 domain of protein kinase C (PKC) is involved in Ca 2+ -and phospholipiddependent activation of proteins (Kaibuchi et al 1989;Wang 2002). Other C2 domains have been reported to act as modules for protein-protein interactions (Miyazaki et al 1995). Recently, the C2 domain of PKC was identiWed as a phosphotyrosine-binding domain (Benes et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of a pepper C2 domain-containing SRC2 protein implicated in resistance against host and non-host pathogens and abiotic stresses

Kim

Choi

et al. 2008

Planta

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Plants guard themselves against pathogen attack using multi-layered defense mechanism. Calcium represents an important secondary messenger during such defense responses. Upon examination of a pepper cDNA library, we observed that the gene CaSRC2-1 (Capsicum annum SRC2-1) was upregulated significantly in response to infection with the type II non-host pathogen Xanthomonas axonopodis pv. glycines 8 ra, which elicits a hypersensitive response. CaSRC2-1 encodes a protein that contains a C2 domain and it exhibits a high degree of homology to the protein Soybean genes regulated by cold 2 (SRC2). However, little is known about how SRC2 expression is elicited by biotic stresses such as pathogen challenge. Further sequence analysis indicated that the CaSRC2-1 C2 domain is unique and contain certain amino acids that are conserved within the C2 domains of other plants and animals. CaSRC2-1 transcription was up-regulated under both biotic and abiotic stress conditions, including bacterial and viral pathogen infection, CaCl(2) and cold treatment, but unaffected by treatment with plant defense-related chemicals such as salicylic acid, methyl jasmonic acid, ethephone, and abscisic acid. Intriguingly, under steady state conditions, CaSRC2-1 was expressed only in the root system. A CaSRC2-1-GFP fusion protein was used to determine localization to the plasma membrane. A fusion protein lacking the C2 domain failed to target the membrane but remained in the cytoplasm, indicating that the C2 domain plays a critical role in localization. Thus, CaSRC2-1 encodes a novel C2 domain-containing protein that targets the plasma membrane and plays a critical role in the abiotic stress and defense responses of pepper plants.

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Rabphilin-3A binds to a Mr 115,000 polypeptide in a phosphatidylserine- and Ca2+-dependent manner

Cited by 19 publications

References 31 publications

Yeast RSP5 and Its Human Homolog hRPF1 Potentiate Hormone-Dependent Activation of Transcription by Human Progesterone and Glucocorticoid Receptors

Yeast RSP5 and Its Human Homolog hRPF1 Potentiate Hormone-Dependent Activation of Transcription by Human Progesterone and Glucocorticoid Receptors

Physical and Functional Interaction of Rabphilin-3A with α-Actinin

Molecular characterization of a pepper C2 domain-containing SRC2 protein implicated in resistance against host and non-host pathogens and abiotic stresses

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