Analyzing the functions of Translationally controlled tumor protein2 during growth, development and autophagy of Dictyostelium discoideum.

Translationally controlled tumor protein (TCTP) is a well conserved and ubiquitously expressed multifunctional protein found in many organisms and is involved in many pathophysiological processes like cell proliferation, differentiation, development and cell death. The role of TCTP in anti-apoptosis and cancer metastasis makes it a promising candidate for cancer therapy. Dictyostelium discoideum, a protist, has two isoforms (TCTP1 and TCTP2, now referred to as TPT1 and TPT2) of which we have earlier elucidated TPT1.

Deletion of Dictyostelium tpc2 gene forms multi-tipped structures, regulates autophagy and cell-type patterning.

Background Information: Two pore channels (TPCs) are voltage-gated ion channel superfamily members that release Ca from acidic intracellular stores and are ubiquitously present in both animals and plants. Starvation initiates multicellular development in Dictyostelium discoideum. Increased intracellular calcium levels bias Dictyostelium cells towards the stalk pathway and thus we decided to analyze the role of TPC2 in development, differentiation, and autophagy.

Metabolic signals influence cell-fate decisions in Dictyostelium discoideum.

Nutrient-sensing plays a crucial role in maintaining cellular energy and metabolic homeostasis. Perturbations in sensing pathways are associated with a wide variety of pathologies, especially metabolic diseases. Very little is understood about sensing fluctuations in nutrients and how this information is integrated into physiological and metabolic adaptation that could further affect cell-fate decisions during differentiation in Dictyostelium discoideum (henceafter, Dictyostelium).

Comparative modelling unravels the structural features of eukaryotic TCTP implicated in its multifunctional properties: an in silico approach.

Comparative modelling helps compare the structure and functions of a given protein, to track the path of its origin and evolution and also guide in structure-based drug discovery. Presently, this has been applied for modelling the tertiary structure of highly conserved eukaryotic TCTP (translationally controlled tumour protein) which is involved in a plethora of functions during growth and development and also acts as a biomarker for many cancers like lung, breast, and prostate cancer. The modelled TCTP structures of different organisms belonging to the eukaryotic group showed similar spatial arrangement of structural units except loops and similar patterns of root mean square deviation (RMSD), root mean square fluctuation, and radius of gyration (Rg) inspected through molecular dynamics simulations.

Investigating the Role of Translationally Control Tumor Protein in Growth, Development and Differentiation of .

Translationally controlled tumor protein (TCTP) is a multifunctional protein implicated in various types of cellular processes involving growth and development of an organism. Here, we identified gene in and unraveled its function. The sequence analysis of TCTP (TCTP) showed its conservation among eukaryotes.

Glimpses of Dictyostelid research in India.

Simple organisms are preferred for understanding the molecular and cellular function(s) of complex processes. Dictyostelium discoideum is a lower eukaryote, a protist and a cellular slime mould, which has been in recent times used for various studies such as cell differentiation, development, cell death, stress responses etc. It is a soil amoeba (unicellular) that undertakes a remarkable, facultative shift to multicellularity when exposed to starvation and requires signal pathways that result in alteration of gene expression and finally show cell differentiation.

AMPKα promotes basal autophagy induction in Dictyostelium discoideum.

Autophagy is a degradation process, wherein long-lived proteins, damaged organelles, and protein aggregates are degraded to maintain cellular homeostasis. Upon starvation, 5'-AMP-activated protein kinase (AMPK) initiates autophagy. We show that ampkα cells exhibit 50% reduction in pinocytosis and display defective phagocytosis.

Deletion of Htt cause alterations in cAMP signaling and spatial patterning in Dictyostelium discoideum.

In the present study, we have analyzed in detail the functions of Htt during growth and development of the protist, Dictyostelium discoideum by creating mutants (both overexpressor and knockout). The mRNA was present at all stages of growth and development. Overexpression of htt did not show any major anomaly, while deletion resulted in delayed aggregation territory formation and showed asynchronous development especially after slug stage.

Overexpression of S-adenosylmethionine decarboxylase impacts polyamine homeostasis during development of Dictyostelium discoideum.

The polyamines putrescine, spermidine and spermine are essential polycations involved in the regulation of cellular proliferation. They exert dynamic effects on nucleic acids and macromolecular synthesis in vitro but their specific functions in vivo are poorly understood. Here, we have modulated the spermidine levels either by overexpressing the S-adenosylmethionine decarboxylase (samdc) gene or treating the cells with methylglyoxal-bis (guanylhydrazone) (MGBG), an inhibitor of SAMDC.

Crucial role of poly (ADP-ribose) polymerase (PARP-1) in cellular proliferation of Dictyostelium discoideum.

The unicellular, as well as multicellular stages of Dictyostelium discoideum's life cycle, make it an excellent model system for cell type determination, differentiation, development, and cell death studies. Our preliminary results show the involvement of poly (ADP-ribose) polymerase-1 (PARP-1) during D. discoideum growth by its constitutive downregulation as well as by its ortholog overexpression.

Deletion of etoposide-induced 2.4 kb transcript (ei24) reduced cell proliferation and aggregate-size in Dictyostelium discoideum.

The etoposide-induced 2.4 kb transcript (ei24) gene is induced both by p53 and etoposide, an anti-cancer tumour drug. There is no p53 gene present in Dictyostelium discoideum.

Deletion of Dictyostelium discoideum Sir2A impairs cell proliferation and inhibits autophagy.

Sirtuins are a family of deacetylases (Class III histone deacetylases) with evolutionarily conserved functions in cellular metabolism and chromatin regulation. Out of the seven human Sirtuins, the function of Sirt2 is the least understood. The purpose of the present study was to investigate the role of Sir2A, a homolog of human Sirt2 in Dictyostelium discoideum (Dd), a lower eukaryote.

Structure, molecular dynamics simulation, and docking studies of Dictyostelium discoideum and human STRAPs.

The Serine Threonine kinase Receptor Associated Protein (STRAP) is a WD40 containing protein that provides a platform for protein interactions during cell proliferation and development. Overexpression and misregulation of STRAP contributes to various carcinomas that are now recognized as therapeutic targets especially for colorectal and lung cancers. The present study was undertaken to find an effective drug against this molecule using a simple system like Dictyostelium discoideum; which shares close homology to humans.

Introducing a simple model system for binding studies of known and novel inhibitors of AMPK: a therapeutic target for prostate cancer.

Prostate cancer (PC) is one of the leading cancers in men, raising a serious health issue worldwide. Due to lack of suitable biomarker, their inhibitors and the platform for testing those inhibitors result in poor prognosis of PC. AMP-activated protein kinase (AMPK) is a highly conserved protein kinase found in eukaryotes that is involved in growth and development, and also acts as a therapeutic target for PC.

AMPKα regulates aggregate size and cell-type patterning.

Starved cells aggregate into groups of nearly 10 cells. AMPK is a highly conserved serine/threonine protein kinase consisting of a catalytic and two regulatory subunits. As multi-cellular development in is initiated upon starvation, we explored the role of the energy sensor, AMPK, which shows significant similarity to human AMPK and is expressed throughout development.

Identification of novel inhibitors of the translationally controlled tumor protein (TCTP): insights from molecular dynamics.

The translationally controlled tumor protein (TCTP) is a highly conserved multifunctional protein, preferentially expressed in mitotically active tissues and is a potential biomarker and a therapeutic target for lung cancers. An understanding of the biology of this molecule and model systems for the screening of drugs is still awaited. In the absence of complete crystal structure, NMR structures as templates were used for homology modeling and MD optimization of both Dictyostelium discoideum and human TCTPs, which was followed by pocket-site prediction, ligand screening and docking.

Disruption of homeobox containing gene, hbx9 results in the deregulation of prestalk cell patterning in Dictyostelium discoideum.

We have earlier classified the homeobox containing genes from Dictyostelium discoideum and identified 5 genes belonging to the TALE class. Here, we have characterized hbx9, a member of TALE class. In situ hybridization results show it to be preferentially expressed in the prestalkA (pstA) cells but not in the prestalkO (pstO) cells.

Dictyostelium discoideum Sir2D modulates cell-type specific gene expression and is involved in autophagy.

Sirtuins (SIRTs) belong to class III histone deacetylases and require NAD for their activity. Their activity is associated with the nutritional status of the cell and they directly link cellular metabolic signalling to the state of protein post-translational modifications. Sirtuins play an important role in healthy aging, longevity and age-related diseases, as well as in cell survival mechanisms, such as autophagy.

Poly (ADP-ribose) polymerase1 regulates growth and multicellularity in D. discoideum.

Poly (ADP-ribose) polymerase (PARP)-1 regulates various biological processes like DNA repair, cell death etc. However, the role of PARP-1 in growth and differentiation still remains elusive. The present study has been undertaken to understand the role of PARP-1 in growth and development of a unicellular eukaryote, Dictyostelium discoideum.

Overexpression of TOR (target of rapamycin) inhibits cell proliferation in Dictyostelium discoideum.

TOR (target of rapamycin) protein kinase acts as a central controller of cell growth and development of an organism. Present study was undertaken to find the expression pattern and role of TOR during growth and development of Dictyostelium discoideum. Failures to generate either knockout and/or knockdown mutants indicate that interference with its levels led to cellular defects.

Classification and expression analyses of homeobox genes from Dictyostelium discoideum.

Homeobox genes are compared between genomes in an attempt to understand the evolution of animal development. The ability of the protist, Dictyostelium discoideum, to shift between uni- and multicellularity makes this group ideal for studying the genetic changes that may have occurred during this transition. We present here the first genome-wide classification and comparative genomic analysis of the 14 homeobox genes present in D.

Analysis of rapamycin induced autophagy in Dictyostelium discoideum.

Natural autophagy and autophagic cell death is being studied in the model system, D. discoideum, which has well known genetic and experimental advantages over the other known systems. There is no apoptotic machinery present in this organism which could interfere with the non-apoptotic cell death.

Peptide: N- glycanase is expressed in prestalk cells and plays a role in the differentiation of prespore cells during development of Dictyostelium discoideum.

Peptide: N-glycanase (PNGase) enzyme is found throughout eukaryotes and plays an important role in the misfolded glycoprotein degradation pathway. This communication reports the expression patterns of the pngase transcript (as studied by the analysis of beta-galactosidase reporter driven by the putative pngase promoter) and protein (as studied by the analysis of beta-galactosidase reporter expressed under the putative pngase promoter as a fusion with the pngase ORF) during development and further elucidated the developmental defects of the cells lacking PNGase (png(-)). The results show that the DdPNGase is an essential protein expressed throughout development and beta-galactosidase activity was present in the anterior part of the slug.