The Jimenez-Ruiz Laboratory is dedicated to unraveling the molecular mechanisms that govern cytoskeletal regulation and motility in apicomplexan parasites. Our research focuses on post-translational modifications (PTMs) as key regulatory processes shaping parasite development, invasion, and dissemination.
Among the differents post-translational modifications (PTMs), methylation has emerged as a crucial yet underexplored factor influencing cytoskeletal dynamics. By investigating the methylation landscape in Toxoplasma gondii and Plasmodium falciparum, we aim to uncover how these modifications impact parasite motility, force transmission, and survival within the host. Using an integrative approach that combines biochemical, genetic, imaging, and proteomic techniques, our work seeks to advance the understanding of cytoskeletal regulation and its implications for apicomplexan pathogenesis.
Methylation plays a fundamental role in regulating cellular processes across eukaryotes, influencing gene expression, protein stability, signal transduction, and cytoskeletal organization. While well-studied in higher organisms, methylation in unicellular protozoan parasites remains largely unexplored. Our research aims to decipher how this modification has been adapted to support the unique cellular architecture and motility of apicomplexans.
Recent studies have identified methylation machinery in T. gondii and P. falciparum, linking it to key regulatory processes such as cytoskeletal remodeling, stress response, and stage conversion. In T. gondii, methylation of cytoskeletal proteins plays a pivotal role in regulating the actomyosin system, which is essential for parasite gliding motility, host-cell invasion, and egress. Similarly, in P. falciparum, methylation events have been associated with both cytoskeletal function and epigenetic regulation, highlighting their importance in parasite survival and adaptation.
AKMT (Apical Lysine (K) Methyltransferase) was initially described as a key player in parasite motility by directly modifying cytoskeletal proteins, influencing microtubule stability, conoid extrusion, and force transmission. However, our lab has expanded this research by identifying additional methyltransferases that also regulate motility and other essential processes unrelated to epigenetics. These newly discovered methyltransferases contribute to actin dynamics, trafficking and parasite invasion, underscoring the broader role of methylation in cellular mechanics beyond gene regulation. By characterizing these enzymes and their substrates, we aim to provide a comprehensive understanding of how methylation fine-tunes cytoskeletal function and parasite movement.
Our laboratory employs a multidisciplinary approach to investigate the role of methylation and other PTMs in parasite biology. Key methodologies include:
· Mass spectrometry-based proteomics: To map the methylation landscape and identify modified proteins.
· Conditional gene knockouts/knockdowns: To dissect the roles of specific methyltransferases and demethylases.
· Advanced live-cell imaging and super-resolution microscopy: To visualize cytoskeletal dynamics and motility in real time.
· Biochemical assays and protein interaction studies: To characterize substrate-specific methylation events and their functional consequences.
· Genetic engineering and site-directed mutagenesis: To assess the impact of specific methylation sites on protein function.
By integrating these cutting-edge approaches, we aim to bridge the gap between post-translational modifications and parasite motility. Our research not only advances fundamental parasitology but also contributes to the development of novel therapeutic strategies against parasitic diseases such as toxoplasmosis and malaria.