izvor podataka: poirot

Nekanonske uloge aminoacil-tRNA-sintetaza

Non-canonical roles of aminoacyl-tRNA synthetases


U suradnji s domaćim i stranim partnerima studirat ćemo neuobičajene ili nekanonske uloge aminoacil-tRNA-sintetaza (aaRS) u prijenosu genetičke poruke i drugim staničnim procesima. AaRS su esencijalni enzimi u stanici, koji kataliziraju esterifikaciju transfer RNA pripadnim aminokiselinama. Nastale aminoacil-tRNA sudjeluju u biosintezi proteina na ribosomu. Međutim, nedavno su otkrivene i druge (nekanonske) funkcije tih enzima. U svim domenama života aaRS tvore makromolekulske komplekse s drugim sintetazama i/ili s nesintetaznim proteinima. Takva združivanja mogu mijenjati funkciju i lokalizaciju sintetaza u stanici. U arhejama smo identificirali sintetazni kompleks koji se veže na ribosome. Istražit ćemo posljedice formiranja takvog super-kompleksa na efikasnost i točnost translacije. Multi-sintetazni kompleksi bi mogli poslužiti i kao "skladišta" sintetaza. Promjene uvjeta u stanici utjecat će na oslobađanje sintetaza iz repozitorija i omogućiti im obavljanje nekanonskih zadaća izvan translacije, primjerice u degradaciji proteina. K tome, proteini nalik aminoacil-tRNA-sintetazama, izvorne veličine ili skraćeni, sudjeluju u neribosomskoj sintezi peptida i drugih prirodnih spojeva. Nedavno smo opisali skraćene homologe seril-tRNA-sintetaza koji ne aminoaciliraju tRNA, već prenose aktivirane aminokiseline na specifične proteine-nosače. Istražujemo produkte i funkcije tih novootkrivenih biosintetskih putova. U planu je pilot-studij o povezanosti disregulacije aaRS i razvoja tumora. Naša su istraživanja temeljna, s potencijalnom primjenom u farmakologiji i zdravstvu.

In collaboration with foreign and domestic partners, we will study newly discovered unusual or non-canonical roles of aminoacyl-tRNA synthetases (aaRSs) in transmission of genetic information and in other cellular processes. As housekeeping enzymes, aaRSs catalyze the specific coupling of amino acids with their cognate tRNAs to produce aminoacyl-tRNAs, which serve as starting materials for protein biosynthesis. Recent studies performed by us and the others revealed that these enzymes are much more versatile than initially thought. In all three domains of life they form macromolecular assemblies with other aaRSs and various non-synthetase proteins. These associations affect synthetase functions and their localization in the cell. In archaea we have identified a multi-synthetase complex, which associates with the ribosome and our objectives are now to investigate the consequences of complex formation with respect to the function of individual components and the protein synthesis machinery in general. By characterizing the effects of complex formation on protein synthesis, we will begin to resolve how such assemblies control the efficiency and accuracy of translation. In support, recent genome wide analyses of gene structure and codon usage strongly suggest that such complexes may be critical for channeling substrates during protein synthesis and optimization of translation. They may also act as a repository for aaRSs. In response to cellular changes, aaRSs are subsequently liberated from the complex to participate in non-canonical tasks beyond translation, such as protein degradation or regulation of transcription and metabolism. Our preliminary in vivo screens, revealing interesting protein interactors of aaRSs, support the role of aaRS complexes in protein homeostasis. Finally, aaRS homologs, full-lengths or truncated, take a part in non-ribosomal synthesis of natural products, emphasizing diversity of functions displayed by aaRS super-family. Seryl-tRNA synthetases (SerRSs), studied in our laboratory for many years, will be further employed as excellent model system, because these enzymes display unique structural and functional characteristics. Three types of SerRSs exist: canonical or bacterial-type SerRSs function in majority of organisms (our current focus is on plant enzymes), a highly diverged atypical methanogenic-type SerRS is confined only to the methanogenic archaea (we have characterized several representatives), while the third type is truncated SerRS-like form. We have recently described the structure and partly the function of these truncated SerRS-like enzymes, which do not aminoacylate tRNAs, but transfer activated amino acids to specific carrier proteins, representing a link between programmable protein biosynthesis and template-independent peptide synthesis. The objective of this project is to resolve structural, functional and mechanistic diversities of SerRS super-family in fundamental biological processes and possibly highlight and exploit their biomedical values. Our existing collaborations with foreign and domestic macromolecular crystallographers (Dr. Nenad Ban, ETH, Zurich and Dr. Marija Luic, Rudjer Boskovic Institute, Zagreb), molecular geneticists (Dr. Michaela Ibba, Ohio State University, Columbus, Ohio and Dr. Hauke Hennecke, ETH, Zurich) and recently a biophysicist (Dr. Gregor Anderluh, University of Ljubljana) will allow performing an innovative research which will in a broader context compare ribosomal and non-ribosomal peptide synthesis, and elucidate the role of synthetase multitasking in processes beyond translation. Proposed structure-functional studies on aaRS assemblies and synthetase-like proteins are primarily of fundamental nature and have a strong educational impact by involving young researchers. Besides, the results are expected to be applicable. Structural studies on synthetases will direct the structure-based design of inhibitors of these essential enzymes, while understanding the role of individual enzymes participating in to non-ribosomal peptide synthesis may allow engineering of biosynthetic pathways yielding molecules with novel activities. A pilot study will be commenced in collaboration with Dr. Tvrtko Hudolin (Clinical Hospital Center, Zagreb) aiming to explore potential dysregulation of aaRSs, primarily SerRS, in kidney and prostate cancer progression.


aminoacil-tRNA-sintetaze, nekanonske uloge, multiproteinski kompleksi, neribosomska sinteza peptida

aminoacyl-tRNA synthetases, non-canonical roles, multiprotein complexes, nonribosomal peptide synthesis

Znanstveno-istraživački projekti

nije evidentirano

09.01/293

01.01.2013

01.04.2016

nije evidentirano

HRK 1.325.000,00