Biology subjects

Martinez Peralta, G.

Publications and source records attributed to Martinez Peralta, G..

3 recordsLinked to original sources

bioRxiv2026

Proteomic mapping of novel tubulin post-translational modifications in Trypanosoma cruzi cytoskeleton

Microtubules (MTs) play central roles in the organization and morphology of trypanosomatid parasites, forming highly specialized cytoskeletal structures such as the subpellicular corset, the flagellar axoneme, and the mitotic spindle. Functional specialization of MTs is regulated by the "tubulin code", which is defined by the combination of different - and {beta}-tubulin isotypes, a set of post-translational modifications (PTMs) and specific MT-binding proteins. Although multiple tubulin PTMs have been described in trypanosomatids using specific antibodies or mass spectrometry, to date no comprehensive mapping has been reported in Trypanosoma cruzi, the causative agent of Chagas Disease. In the present work, we performed a high-resolution proteomic analysis of PTMs present in - and {beta}-tubulin subunits of the T. cruzi Dm28c strain, using tubulin-enriched extracts obtained by in vitro polymerization. Multiple PTMs were identified, including acetylation, methylation, phosphorylation, and polyglutamylation, for which many modified amino acids had not been previously reported in trypanosomatids. Structural mapping of these modifications onto a predicted /{beta}-tubulin heterodimer showed that most modified residues are located in solvent-exposed regions of the protein. Together, these findings provide the first systematic map of tubulin PTMs in T. cruzi and support the existence of a complex tubulin code contributing to microtubule regulation in this parasite.

cell biology↗

bioRxiv2026

Structural Insights into Bromodomain-Containing Complexes from Trypanosoma cruzi Revealed by Proximity Labeling and Stoichiometric Space Exploration

Trypanosoma cruzi is the causative agent of Chagas disease, a neglected illness with outdated treatments. Bromodomain factors (BDFs) are essential proteins that recognize acetylated lysines and have strong therapeutic potential. They form part of epigenetic complexes that regulate chromatin accessibility and, therefore, gene expression. However, little is known about their structure in trypanosomatids. Here, we used a combination of experimental and bioinformatic approaches to infer the stoichiometry and structure of T. cruzi bromodomain-containing complexes. By reconstructing the proximity networks of five BDFs using TurboID-directed proximity labeling, we identified highly interconnected components that assemble into the CRKT and NuA4 complexes. Using novel structure prediction strategies that systematically explore the stoichiometric space, we inferred that CRKT assembles into three distinct modules and NuA4 in two, with different degrees of interaction dynamics. The core module of CRKT contains two copies of each component, including BDF3, BDF5, and BDF8, arranged in a subcomplex with central symmetry. The catalytic module of CRKT has three subunits, including the histone acetyltransferase 2 (HAT2), while the BET (bromodomain and extra-terminal) module has one unit of both BDF4 and BDF1. The catalytic module of NuA4 closely resembles the yeast piccolo-NuA4 module and contains HAT1, while the TINTIN module associates with the catalytic module via the C-terminal domain of BDF6. These insights shed light on the structure and composition of epigenetic complexes in trypanosomatids, opening new avenues for rational drug design aimed at disrupting their function.

molecular biology↗

bioRxiv2020

Alpha-tubulin acetylation in Trypanosoma cruzi: a dynamic instability of microtubules is required for replication and cell cycle progression

Trypanosomatids have a cytoskeleton arrangement that is simpler than what is found in most eukaryotic cells. However, it is precisely organized and constituted by stable microtubules. Such microtubules compose the mitotic spindle during mitosis, the basal body, the flagellar axoneme and the subpellicular microtubules, which are connected to each other and also to the plasma membrane forming a helical arrangement along the central axis of the parasite cell body. Subpellicular, mitotic and axonemal microtubules are extensively acetylated in Trypanosoma cruzi. Acetylation on lysine (K) 40 of -tubulin is conserved from lower eukaryotes to mammals and is associated with microtubule stability. It is also known that K40 acetylation occurs significantly on flagella, centrioles, cilia, basal body and the mitotic spindle in eukaryotes. Several tubulin posttranslational modifications, including acetylation of K40, have been catalogued in trypanosomatids, but the functional importance of these modifications for microtubule dynamics and parasite biology remains largely undefined. The primary tubulin acetyltransferase that delivers this modification was recently identified in several eukaryotes as Mec-17/ATAT, a Gcn5-related N-acetyltransferase. Here, we report that T. cruzi ATAT acetylates -tubulin in vivo and is capable of auto-acetylation. TcATAT is located in the cytoskeleton and flagella of epimastigotes and colocalizes with acetylated -tubulin in these structures. We have expressed TcATAT with an HA tag using the inducible vector pTcINDEX-GW in T. cruzi. Over-expression of TcATAT causes increased levels of the acetylated isoform, induces morphological and ultrastructural defects, especially in the mitochondrion, and causes a halt in the cell cycle progression of epimastigotes, which is related to an impairment of the kinetoplast division. Finally, as a result of TcATAT over-expression we observed that parasites became more resistant to microtubule depolymerizing drugs. These results support the idea that -tubulin acetylation levels are finely regulated for the normal progression of T. cruzi cell cycle.

cell biology↗