Impaired fibroblast growth factor receptor (FGFR) signaling is associated with many human conditions, including growth disorders, degenerative diseases, and cancer. Current FGFR therapeutics are based on chemical inhibitors of FGFR tyrosine kinase activity (TKIs). However, FGFR TKIs are limited in their target specificity as they generally inhibit all FGFRs and other receptor tyrosine kinases. In the search for specific inhibitors of human FGFR1, we identified VZ23, a DNA aptamer that binds to FGFR1b and FGFR1c with a KD of 55 nM and 162 nM, respectively, but not to the other FGFR variants (FGFR2b, FGFR2c, FGFR3b, FGFR3c, FGFR4). In cells, VZ23 inhibited the activation of downstream FGFR1 signaling and FGFR1-mediated regulation of cellular senescence, proliferation, and extracellular matrix homeostasis. Consistent with the specificity toward FGFR1 observed in vitro, VZ23 did not inhibit FGFR2-4 signaling in cells. We show that the VZ23 inhibits FGFR1 signaling in the presence of cognate fibroblast growth factor (FGF) ligands and its inhibitory activity is linked to its capacity to form unusual G-quadruplex structure. Our data suggest that targeting FGFR1 with DNA aptamers could be an effective alternative to TKIs for treating impaired FGFR1 signaling in human craniosynostoses.
- Publikační typ
- časopisecké články MeSH
Protein import and genome replication are essential processes for mitochondrial biogenesis and propagation. The J-domain proteins Pam16 and Pam18 regulate the presequence translocase of the mitochondrial inner membrane. In the protozoan Trypanosoma brucei, their counterparts are TbPam16 and TbPam18, which are essential for the procyclic form (PCF) of the parasite, though not involved in mitochondrial protein import. Here, we show that during evolution, the 2 proteins have been repurposed to regulate the replication of maxicircles within the intricate kDNA network, the most complex mitochondrial genome known. TbPam18 and TbPam16 have inactive J-domains suggesting a function independent of heat shock proteins. However, their single transmembrane domain is essential for function. Pulldown of TbPam16 identifies a putative client protein, termed MaRF11, the depletion of which causes the selective loss of maxicircles, akin to the effects observed for TbPam18 and TbPam16. Moreover, depletion of the mitochondrial proteasome results in increased levels of MaRF11. Thus, we have discovered a protein complex comprising TbPam18, TbPam16, and MaRF11, that controls maxicircle replication. We propose a working model in which the matrix protein MaRF11 functions downstream of the 2 integral inner membrane proteins TbPam18 and TbPam16. Moreover, we suggest that the levels of MaRF11 are controlled by the mitochondrial proteasome.
- MeSH
- mitochondriální DNA * genetika metabolismus MeSH
- mitochondriální proteiny metabolismus genetika MeSH
- mitochondrie metabolismus genetika MeSH
- molekulární evoluce MeSH
- protozoální proteiny * metabolismus genetika MeSH
- replikace DNA * MeSH
- Trypanosoma brucei brucei * metabolismus genetika MeSH
- Publikační typ
- časopisecké články MeSH
Receptor adenylate cyclases (RACs) on the surface of trypanosomatids are important players in the host-parasite interface. They detect still unidentified environmental signals that affect the parasites' responses to host immune challenge, coordination of social motility, and regulation of cell division. A lesser known class of oxygen-sensing adenylate cyclases (OACs) related to RACs has been lost in trypanosomes and expanded mostly in Leishmania species and related insect-dwelling trypanosomatids. In this work, we have undertaken a large-scale phylogenetic analysis of both classes of adenylate cyclases (ACs) in trypanosomatids and the free-living Bodo saltans. We observe that the expanded RAC repertoire in trypanosomatids with a two-host life cycle is not only associated with an extracellular lifestyle within the vertebrate host, but also with a complex path through the insect vector involving several life cycle stages. In Trypanosoma brucei, RACs are split into two major clades, which significantly differ in their expression profiles in the mammalian host and the insect vector. RACs of the closely related Trypanosoma congolense are intermingled within these two clades, supporting early RAC diversification. Subspecies of T. brucei that have lost the capacity to infect insects exhibit high numbers of pseudogenized RACs, suggesting many of these proteins have become redundant upon the acquisition of a single-host life cycle. OACs appear to be an innovation occurring after the expansion of RACs in trypanosomatids. Endosymbiont-harboring trypanosomatids exhibit a diversification of OACs, whereas these proteins are pseudogenized in Leishmania subgenus Viannia. This analysis sheds light on how ACs have evolved to allow diverse trypanosomatids to occupy multifarious niches and assume various lifestyles.
ZapE/Afg1 is a component of the inner cell membrane of some eubacteria and the inner mitochondrial membrane of eukaryotes. This protein is involved in FtsZ-dependent division of eubacteria. In the yeast and human mitochondrion, ZapE/Afg1 likely interacts with Oxa1 and facilitates the degradation of mitochondrion-encoded subunits of respiratory complexes. Furthermore, the depletion of ZapE increases resistance to apoptosis, decreases oxidative stress tolerance, and impacts mitochondrial protein homeostasis. It remains unclear whether ZapE is a multifunctional protein, or whether some of the described effects are just secondary phenotypes. Here, we have analyzed the functions of ZapE in Trypanosoma brucei, a parasitic protist, and an important model organism. Using a newly developed proximity-dependent biotinylation approach (BioID2), we have identified the inner mitochondrial membrane insertase Oxa1 among three putative interacting partners of ZapE, which is present in two paralogs. RNAi-mediated depletion of both ZapE paralogs likely affected the function of respiratory complexes I and IV. Consistently, we show that the distribution of mitochondrial ZapE is restricted only to organisms with Oxa1, respiratory complexes, and a mitochondrial genome. We propose that the evolutionarily conserved interaction of ZapE with Oxa1, which is required for proper insertion of many inner mitochondrial membrane proteins, is behind the multifaceted phenotype caused by the ablation of ZapE.
- MeSH
- biotinylace MeSH
- delece genu * MeSH
- down regulace MeSH
- Eukaryota genetika MeSH
- fenotyp MeSH
- fylogeneze MeSH
- genom mitochondriální MeSH
- mitochondriální proteiny metabolismus MeSH
- mitochondrie metabolismus MeSH
- protozoální proteiny metabolismus MeSH
- respirační komplex I metabolismus MeSH
- respirační komplex IV metabolismus MeSH
- Trypanosoma brucei brucei metabolismus MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
