Publications by authors named "Jennifer Porat"

Article Synopsis
  • KEOPS is a crucial enzyme complex that modifies tRNAs, specifically adding a N-threonylcarbamoyl adenosine (tA) modification essential for protein synthesis in eukaryotes and archaea.
  • Mutations in any of the KEOPS subunits can cause Galloway Mowat Syndrome (GAMOS) in humans, highlighting the complex's significance in cellular function.
  • Recent cryogenic electron microscopy studies revealed how KEOPS interacts with tRNA, showing that its structure changes during modification and emphasizing the roles of all subunits, especially Bud32, in regulating tRNA modification.
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There is an increasing appreciation for the role of cell surface glycans in modulating interactions with extracellular ligands and participating in intercellular communication. We recently reported the existence of sialoglycoRNAs, where mammalian small RNAs are covalently linked to N-glycans through the modified base acpU and trafficked to the cell surface. However, little is currently known about the role for O-glycosylation, another major class of carbohydrate polymer modifications.

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GlycoRNA consists of RNAs modified with secretory N-glycans that are presented on the cell surface. Although previous work supported a covalent linkage between RNA and glycans, the direct chemical nature of the RNA-glycan connection was not described. Here, we develop a sensitive and scalable protocol to detect and characterize native glycoRNAs.

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tRNAs undergo an extensive maturation process involving posttranscriptional modifications often associated with tRNA structural stability and promoting the native fold. Impaired posttranscriptional modification has been linked to human disease, likely through defects in translation, mitochondrial function, and increased susceptibility to degradation by various tRNA decay pathways. More recently, evidence has emerged that bacterial tRNA modification enzymes can act as tRNA chaperones to guide tRNA folding in a manner independent from catalytic activity.

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Splicing requires the tight coordination of dynamic spliceosomal RNAs and proteins. U6 is the only spliceosomal RNA transcribed by RNA Polymerase III and undergoes an extensive maturation process. In humans and fission yeast, this includes addition of a 5' γ-monomethyl phosphate cap by members of the Bin3/MePCE family as well as snoRNA guided 2'-O-methylation.

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The telomerase holoenzyme is critical for maintaining eukaryotic genome integrity. In addition to a reverse transcriptase and an RNA template, telomerase contains additional proteins that protect the telomerase RNA and promote holoenzyme assembly. Here we report that the methyl phosphate capping enzyme (MePCE) Bmc1/Bin3 is a stable component of the S.

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tRNAs undergo an extensive maturation process including post-transcriptional modifications that influence secondary and tertiary interactions. Precursor and mature tRNAs lacking key modifications are often recognized as aberrant and subsequently targeted for decay, illustrating the importance of modifications in promoting structural integrity. tRNAs also rely on tRNA chaperones to promote the folding of misfolded substrates into functional conformations.

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The KEOPS complex, which is conserved across archaea and eukaryotes, is composed of four core subunits; Pcc1, Kae1, Bud32 and Cgi121. KEOPS is crucial for the fitness of all organisms examined. In humans, pathogenic mutations in KEOPS genes lead to Galloway-Mowat syndrome, an autosomal-recessive disease causing childhood lethality.

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La proteins have well-established roles in the maturation of RNA polymerase III transcripts, including pre-tRNAs. In addition to protecting the 3' end of pre-tRNAs from exonuclease digestion, La proteins also promote the native fold of the pre-tRNA using RNA chaperone activity. tRNA-mediated suppression in the fission yeast S.

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La proteins are RNA chaperones that perform various functions depending on distinct RNA-binding modes and their subcellular localization. In the nucleus, they help process UUU-3'OH-tailed nascent RNA polymerase III transcripts, such as pre-tRNAs, whereas in the cytoplasm they contribute to translation of poly(A)-tailed mRNAs. La accumulation in the nucleus and cytoplasm is controlled by several trafficking elements, including a canonical nuclear localization signal in the extreme C terminus and a nuclear retention element (NRE) in the RNA recognition motif 2 (RRM2) domain.

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