GlSir2.1 of Giardia lamblia is a NAD+-dependent cytoplasmic deacetylase

Herrera, Alfa; Contreras-Rodríguez, Luis Ernesto; Suárez, Aravy G.; Diaz, Gonzalo J.; Ramírez, Miguel Arjona

doi:10.1016/j.heliyon.2019.e01520

Cited by 8 publications

(10 citation statements)

References 43 publications

(68 reference statements)

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“…Interestingly, Sirtuin inhibitor Nicotinamide has been shown to cause G2 arrest of cell cycle 38 . However, our data indicates that mNG-tagged Sirtuin 2.1 only localizes to cytosol at 0 and 1.5 h of encystation (Extended data 10 e,f) which is consistent with other studies 39 , suggesting Sirtuin 2.1 is not involved in regulating early encystation. It will be of particular interest to test whether second messengers have a role in coordinating early encystation, or act as a molecular switch to initiate differentiation into cysts.…”

Section: How Cells Sense Encystation Stimulus But Then Induce Different Responses Based On Cell Cyclesupporting

confidence: 93%

A cell cycle-dependent GARP-like transcriptional repressor regulates the initiation of differentiation in Giardia lamblia

Shih

et al. 2021

Preprint

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Transcriptional regulation of differentiation is critical for parasitic pathogens to adapt to environmental changes and regulate transmission. How early signaling transcription factors (TF) activate signal transduction to initiate encystation remains an open question in Giardia. Here, we generate a CasRX-mediated knockdown system, together with an established CRISPRi system to screen early signaling TFs in Giardia lamblia. We identified an early response TF, GARP4 that regulates cyst wall protein (CWP) levels during encystation. Depletion of GARP4 increases encystation efficiency resulting in increased cyst production. Interestingly, cyst viability and CWP1 trafficking are not altered in GARP4 knockdowns, suggesting GARP4 regulates the restriction point controlling the portion of cells that terminally differentiate into cysts. Consistent with previous studies, we find that stimulation of encystation shifts the distribution of cells to the G2/M phase and these cells exhibits higher levels of CWP1, indication that entry into the encystation pathway is cell cycle regulated. Key to this increase of CWP1 in G2/M cells is activation of MYB2, a TF commonly observed during the early phase of encystation in Giardia. Remarkably, activated GARP4 only exhibits in G1/S cells, suggesting it has a role in preventing encystation until G2/M. Furthermore, we demonstrate that depletion of GARP4 activates MYB2 and overexpression of GARP4 represses MYB2. Our findings provide the first molecular mechanism underlying the restriction point regulating differentiation during early signaling of encystation in Giardia lamblia.

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Section: How Cells Sense Encystation Stimulus But Then Induce Different Responses Based On Cell Cyclesupporting

confidence: 93%

A cell cycle-dependent GARP-like transcriptional repressor regulates the initiation of differentiation in Giardia lamblia

Shih

et al. 2021

Preprint

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“…The five Giardia sirtuins are located in different compartments of the cell: GdSir2.1 is located in the cytoplasm (Carranza et al., 2016; Herrera et al, 2019); GdSir2.2, GdSir2.4, and GdSir2.5 are in the nucleus; and GdSir2.3 is in the perinuclear region (Carranza et al., 2016; Wang et al., 2016). During Giardia encystation, GdSir2.1 expression decreases and GdSir2.3 expression increased (Einarsson, Troell, et al., 2016).…”

Section: Discussionmentioning

confidence: 99%

“…Giardia has five sirtuins: GdSir2.1 (GL50803_10708), GdSir2.2 (GL50803_10707), GdSir2.3 (GL50803_16569), GdSir2.4 (GL50803_11676), and GdSir2.5 (GL50803_6942). Two of those sirtuins (GdSir2.1 and GdSir2.2) have been characterized biochemically (Herrera et al, 2019; Wang et al., 2016), but none of them is known to have a specific function within the parasite.…”

Section: Introductionmentioning

confidence: 99%

Sirtuin GdSir2.4 participates in the regulation of rRNA transcription in the Giardia duodenalis parasite

Lagunas‐Rangel

Yee

García‐Villa

et al. 2021

Molecular Microbiology

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Giardia duodenalis is a parasite of great medical interest due to the number of infections it causes worldwide each year. Although research on epigenetic mechanisms in this protist has only begun recently, epigenetic regulation has already been shown to have important roles in encystation, antigenic variation, and resistance to antibiotics in Giardia. In this work, we show that a Giardia ortholog of Sir2, GdSir2.4, is involved in the silencing of rRNA expression. Our results demonstrate that GdSir2.4 localizes to the nucleolus, and its binding to the intergenic spacer region of the rDNA is associated with the deacetylation of the chromatin in this region. Given the importance of the regulation of rRNA expression to maintain adequate levels of ribosomes and genomic stability within the cells, GdSir2.4 can be considered a target to create new therapeutic agents against this parasite.

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“…Then they were pulverized and the protein was eluted with deionized water at 37 °C under constant agitation. The purification process was followed by SDS-PAGE at 12 %(w/v) and the resultant protein was quantified by densitometry using ImageJ software ( Herrera et al, 2019 ).…”

Section: Methodsmentioning

confidence: 99%

Identification and sub-cellular localization of a NAD transporter in Leishmania braziliensis (LbNDT1)

Herrera

Contreras-Rodríguez

Castellanos

et al. 2020

Heliyon

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Nicotinamide adenine dinucleotide (NAD) is one of the central molecules involved in energy homeostasis, cellular signaling and antioxidative defense systems. Consequently, its biosynthetic pathways and transport systems are of vital importance. The nicotinamide/nicotinate mononucleotide adenylyltransferase (NMNAT), a key enzyme in the biosynthesis of NAD, is distributed in all domains of life and exhibits various isoforms in free-living organisms in contrast with intracellular parasites, which displays a single enzyme. In Leishmania braziliensis a unique cytosolic NMNAT has been reported to date and the mechanisms through which adequate levels of NAD are maintained among the different sub-cellular compartments of this parasite are unknown. Experimental evidences have related the transport of NAD to the Nucleotide Transporters (NTTs) family, whose members are located in the cytoplasmic membrane of parasitic life organisms. Additionally, the Mitochondrial Carrier Family (MCF), a group of proteins located in the membrane of internal organelles such as the mitochondria of free life organisms, has been implicated in NAD transport. Applying bioinformatics tools, the main characteristics of the MCF were found in a transporter candidate that we have designated as Nicotinamide Adenine Dinucleotide Transporter 1 of L. braziliensis ( Lb NDT1). The expression of Lb NDT1 was tested both in axenic amastigotes and promastigotes of L. braziliensis , through immunodetection using polyclonal avian antibodies produced in this study. N-glycosylation of Lb NDT1 was observed in both stages. Additionally, a possible partial mitochondrial distribution for Lb NDT1 in amastigotes and a possible glycosomal location in promastigotes are proposed. Finally, the capability of Lb NDT1 to transport NAD was confirmed by complementation assays in Saccharomyces cerevisiae . Our results demonstrate the existence of Lb NDT1 in L. braziliensis becoming the first NAD transporter identified in protozoan parasites to date.

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GlSir2.1 of Giardia lamblia is a NAD+-dependent cytoplasmic deacetylase

Cited by 8 publications

References 43 publications

A cell cycle-dependent GARP-like transcriptional repressor regulates the initiation of differentiation in Giardia lamblia

A cell cycle-dependent GARP-like transcriptional repressor regulates the initiation of differentiation in Giardia lamblia

Sirtuin GdSir2.4 participates in the regulation of rRNA transcription in the Giardia duodenalis parasite

Identification and sub-cellular localization of a NAD transporter in Leishmania braziliensis (LbNDT1)

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