Dataset Information

Coactivator recruitment: a new role for PAS domains in transcriptional regulation by the bHLH-PAS family.

ABSTRACT: Transcriptional regulation is dependent on layers of interactions between transcription factors and coactivators, controlling the specificity, temporal regulation, and extent to which transcriptional programs are executed. A key issue in the field of transcriptional regulation is to identify structural mechanisms by which transcription factors and coactivators build hierarchical protein assemblies. The basic helix-loop-helix Per-ARNT-Sim domain (bHLH-PAS) family of transcriptional regulators comprises both transcription factors and coactivators, which have different functions despite conserved domain architecture. Within this family, the tandem PAS domains typically mediate dimerization of the transcription factors, while C-terminal transactivation domains facilitate the dynamic interplay between transcription factors and coactivators. However, recent studies have shown that the modular PAS domains play an important role in regulating coactivator recruitment and oligomerization status. In this study, we provide a brief overview of the structural and functional studies that have identified a novel protein interaction interface on PAS domains utilized by both transcription factors and coactivators within the bHLH-PAS family.

SUBMITTER: Partch CL

PROVIDER: S-EPMC2872778 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Coactivator recruitment: a new role for PAS domains in transcriptional regulation by the bHLH-PAS family.

Partch Carrie L CL Gardner Kevin H KH

Journal of cellular physiology 20100601 3

Transcriptional regulation is dependent on layers of interactions between transcription factors and coactivators, controlling the specificity, temporal regulation, and extent to which transcriptional programs are executed. A key issue in the field of transcriptional regulation is to identify structural mechanisms by which transcription factors and coactivators build hierarchical protein assemblies. The basic helix-loop-helix Per-ARNT-Sim domain (bHLH-PAS) family of transcriptional regulators com ...[more]

PMID: 20112293

Similar Datasets

Project description:Photoactive yellow protein (PYP) is a model photoreceptor. It binds a p-coumaric acid as a chromophore, thus enabling blue light sensing. The first discovered single-domain PYP from Halorhodospira halophila has been studied thoroughly in terms of its structural dynamics and photochemical properties. However, the evolutionary origins and biological role of PYP homologs are not well understood. Here, we show that PYP is an evolutionarily novel domain family of the ubiquitous PAS (Per-Arnt-Sim) superfamily. It likely originated from the phylum Myxococcota and was then horizontally transferred to representatives of a few other bacterial phyla. We show that PYP is associated with signal transduction either by domain fusion or by genome context. Key cellular functions modulated by PYP-initiated signal transduction pathways likely involve gene expression, motility, and biofilm formation. We identified three clades of the PYP family, one of which is poorly understood and potentially has novel functional properties. The Tyr42, Glu46, and Cys69 residues that are involved in p-coumaric acid binding in the model PYP from H. halophila are well conserved in the PYP family. However, we also identified cases where substitutions in these residues might have led to neofunctionalization, such as the proposed transition from light to redox sensing. Overall, this study provides definition, a newly built hidden Markov model, and the current genomic landscape of the PYP family and sets the stage for the future exploration of its signaling mechanisms and functional diversity. IMPORTANCE Photoactive yellow protein is a model bacterial photoreceptor. For many years, it was considered a prototypical model of the ubiquitous PAS domain superfamily. Here, we show that, in fact, the PYP family is evolutionarily novel, restricted to a few bacterial phyla and distinct from other PAS domains. We also reveal the diversity of PYP-containing signal transduction proteins and their potential mechanisms.

Project description:Hypoxia-inducible factor (HIF), a critical member of the basic-helix-loop-helix (bHLH)-containing Per-Arnt-Sim (PAS) protein family, is a master transcription factor involved in maintaining oxygen homeostasis. In the present study, we isolated and characterized a novel bHLH-PAS family member, CgHIFα-like gene, from the Pacific oyster Crassostrea gigas, and determined its importance during hypoxia stress. The 3020-bp CgHIFα-like cDNA encoded a protein of 888 amino acids. The predicted CgHIFα-like amino acid sequence was conserved in the N-terminal bHLH, PAS, and PAC domains (but not in the C-terminal domain) and was most closely related to the HIF family in the bHLH-PAS protein phylogenic tree. Similar to the mammalian HIF-1α, CgHIFα-like could be expressed as four mRNA isoforms containing alternative 5'-untranslated regions and different translation initiation codons. At the mRNA level, these isoforms were expressed in a tissue-specific manner and showed increased transcription to varying degrees under hypoxic conditions. Additionally, the western blot analysis demonstrated that CgHIFα-like was induced by hypoxia. Electrophoretic mobility shift assay indicated that CgHIFα-like could bind to the hypoxia responsive element (HRE), whereas dual-luciferase reporter analysis demonstrated that CgHIFα-like could transactivate the reporter gene containing the HREs. In addition to CgHIFα-like, we identified CgARNT from the C. gigas, analyzed its expression pattern, and confirmed its interaction with CgHIFα-like using a yeast two-hybrid assay. In conclusion, this is the first report on the cloning and characterization of a novel hypoxia transcription factor in mollusks, which could accumulate under hypoxia and regulate hypoxia related gene expression by binding to HRE and dimerizing with CgARNT. As only one member of HIF has been identified in invertebrates to date, our results provide new insights into the unique mechanisms of hypoxia tolerance in mollusks.

Dataset Information

Coactivator recruitment: a new role for PAS domains in transcriptional regulation by the bHLH-PAS family.

Publications

Coactivator recruitment: a new role for PAS domains in transcriptional regulation by the bHLH-PAS family.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets