Ligand-dependent intracellular trafficking of the G protein-coupled P2Y receptor.

Endosomal trafficking is intricately linked to G protein-coupled receptors (GPCR) fate and signaling. Extracellular uridine diphosphate (UDP) acts as a signaling molecule by selectively activating the GPCR P2Y. Despite the recent interest for this receptor in pathologies, such as gastrointestinal and neurological diseases, there is sparse information on the endosomal trafficking of P2Y receptors in response to its endogenous agonist UDP and synthetic selective agonist 5-iodo-UDP (MRS2693).

The P2Y receptor signals through Gα /Ca /PKCα and Gα /ROCK pathways to drive the formation of membrane protrusions and dictate cell migration.

Cell migration is a ubiquitous process necessary to maintain and restore tissue functions. However, in cancer, cell migration leads to metastasis development and thus worsens the prognosis. Although the mechanism of cell migration is well understood, the identification of new targets modulating cell migration and deciphering their signaling events could lead to new therapies to restore tissue functions in diseases, such as inflammatory bowel disease, or to block metastatic development in different forms of cancer.

The expression of the P2Y receptor is regulated at the transcriptional level by p53.

Inflammatory bowel disease (IBD) is a risk factor for the development of colorectal cancer (CRC) for which mutation to p53 is an early event leading to dysplasia. Interestingly, P2RY6 mRNA increases in both pathologies. In this study, we investigated if p53 and p53 mutant, commonly found in CRC and IBD, were involved in the transcriptional regulation of P2RY6.

Reviewing the role of P2Y receptors in specific gastrointestinal cancers.

Extracellular nucleotides are important intercellular signaling molecules that were found enriched in the tumor microenvironment. In fact, interfering with G protein-coupled P2Y receptor signaling has emerged as a promising therapeutic alternative to treat aggressive and difficult-to-manage cancers such as those affecting the gastrointestinal system. In this review, we will discuss the functions of P2Y receptors in gastrointestinal cancers with an emphasis on colorectal, hepatic, and pancreatic cancers.

Assessing Transcriptional Responses to Light by the Dinoflagellate .

The control of transcription is poorly understood in dinoflagellates, a group of protists whose permanently condensed chromosomes are formed without histones. Furthermore, while transcriptomes contain a number of proteins annotated as transcription factors, the majority of these are cold shock domain proteins which are also known to bind RNA, meaning the number of true transcription factors is unknown. Here we have assessed the transcriptional response to light in the photosynthetic species .

miRNAs Do Not Regulate Circadian Protein Synthesis in the Dinoflagellate Lingulodinium polyedrum.

Dinoflagellates have been shown to express miRNA by bioinformatics and RNA blot (Northern) analyses. However, it is not yet known if miRNAs are able to alter gene expression in this class of organisms. We have assessed the possibility that miRNA may mediate circadian regulation of gene expression in the dinoflagellate Lingulodinium polyedrum using the Luciferin Binding Protein (LBP) as a specific example.

The main nitrate transporter of the dinoflagellate Lingulodinium polyedrum is constitutively expressed and not responsible for daily variations in nitrate uptake rates.

Dinoflagellates are unicellular eukaryotes capable of forming spectacular harmful algal blooms (HABs). Eutrophication of coastal waters by fertilizer runoff, nitrate in particular, has contributed to recent increases in the frequency, magnitude and geographic extent of HABs. Although physiological nitrate uptake and assimilation in dinoflagellates have often been measured in the field and in the laboratory, no molecular components involved in nitrate transport have yet been reported.

The Symbiodinium kawagutii genome illuminates dinoflagellate gene expression and coral symbiosis.

Dinoflagellates are important components of marine ecosystems and essential coral symbionts, yet little is known about their genomes. We report here on the analysis of a high-quality assembly from the 1180-megabase genome of Symbiodinium kawagutii. We annotated protein-coding genes and identified Symbiodinium-specific gene families.

The dinoflagellate Lingulodinium polyedrum responds to N depletion by a polarized deposition of starch and lipid bodies.

Dinoflagellates are important contributors to the marine phytoplankton and global carbon fixation, but are also infamous for their ability to form the spectacular harmful algal blooms called red tides. While blooms are often associated with high available nitrogen, there are instances where they are observed in oligotrophic environments. In order to maintain their massive population in conditions of nitrogen limitation, dinoflagellates must have evolved efficient adaptive mechanisms.

Putting the N in dinoflagellates.

The cosmopolitan presence of dinoflagellates in aquatic habitats is now believed to be a direct consequence of the different trophic modes they have developed through evolution. While heterotrophs ingest food and photoautotrophs photosynthesize, mixotrophic species are able to use both strategies to harvest energy and nutrients. These different trophic modes are of particular importance when nitrogen nutrition is considered.

Dinoflagellate tandem array gene transcripts are highly conserved and not polycistronic.

Dinoflagellates are an important component of the marine biota, but a large genome with high-copy number (up to 5,000) tandem gene arrays has made genomic sequencing problematic. More importantly, little is known about the expression and conservation of these unusual gene arrays. We assembled de novo a gene catalog of 74,655 contigs for the dinoflagellate Lingulodinium polyedrum from RNA-Seq (Illumina) reads.

S-phase and M-phase timing are under independent circadian control in the dinoflagellate Lingulodinium.

In many phytoplankton species, cell division (mitosis) usually occurs at defined times of day. This timing is also observed under constant conditions, indicating that it is regulated by a circadian clock rather than by a simple response to the light-dark cycle. For those algae with cell cycles longer than a day, the clock opens a window of opportunity for mitosis at a particular time of day through which cells in an appropriate phase of the cell cycle can pass.