Biology subjects

Krogh, N.

Publications and source records attributed to Krogh, N..

5 recordsLinked to original sources

bioRxiv2026

Regulation of RNA maturation by the family of human G-patch proteins

The family of human G-patch proteins comprises more than 20 members, each characterized by a glycine-rich G-patch implicated in mediating interactions with RNA helicases. Here, we systematically identify the cognate RNA helicase of each G-patch protein, highlighting the association of DHX15 with a network of 20 G-patch cofactors. DHX35 and GPATCH1 represent a unique G-patch protein-RNA helicase pair, and we uncover a regulatory circuit between these partners. Comprehensive in vitro analyses of ATPase activity and RNA binding identify distinguishing features of DHX15- and non-DHX15-associated G-patch proteins, and demonstrate the roles of most G-patch proteins as bona fide stimulatory cofactors of DHX15. RNA interactome analyses of each G-patch protein and complementary transcriptome-wide alternative splicing analyses in cells lacking a G-patch protein reveal distinct modes of regulation of mRNA maturation by different G-patch proteins. For example, ZGPAT affects splicing indirectly through its requirement for efficient 2'-O-methylation of snRNAs, GPATCH8 exemplifies DHX15-associated alternative splicing modulation, whereas SUGP2 suppresses splicing in an RNA helicase-independent manner via direct binding to pre-mRNA introns.

molecular biology↗

bioRxiv2022

Loss of N-terminal acetyltransferase A activity induces thermally unstable ribosomal proteins and increases their turnover

Protein N-terminal (Nt) acetylation is one of the most abundant modifications in eukaryotes, covering [~]50-80 % of the proteome, depending on species. Cells with defective Nt-acetylation display a wide array of phenotypes such as impaired growth, mating defects and increased stress sensitivity. However, the pleiotropic nature of these effects has hampered our understanding of the functional impact of protein Nt-acetylation. The main enzyme responsible for Nt-acetylation throughout the eukaryotic kingdom is the N-terminal acetyltransferase NatA. Here we employed a multi-dimensional proteomics approach to analyze Saccharomyces cerevisiae lacking NatA activity, which caused global proteome remodeling. Pulsed-SILAC experiments revealed that NatA-deficient strains consistently increased degradation of ribosomal proteins compared to wild type. Explaining this phenomenon, thermal proteome profiling uncovered decreased thermostability of ribosomes in NatA-knockouts. Our data are in agreement with a role for Nt-acetylation in promoting stability for parts of the proteome by enhancing the avidity of protein-protein interactions and folding. TeaserA multidimensional proteomics approach reveals the effect of N-terminal acetylation on Saccharomyces cerevisiae cytosolic ribosomal proteins.

biochemistry↗

bioRxiv2022

Ribosomal RNA 2'-O-methylation dynamics impact cell fate decisions

Translational regulation impacts both pluripotency maintenance and cell differentiation. To what degree the ribosome itself exerts control over this process remains unanswered. Accumulating evidence has demonstrated heterogeneity in ribosome composition in various organisms. 2-O-methylation of rRNA represents an important source of heterogeneity, where site-specific alteration of methylation levels can modulate translation. Here we explore changes in rRNA 2-O-methylation during mouse brain development and during tri-lineage differentiation of human embryonic stem cells. We find distinct alterations between brain regions, as well as clear dynamics during cortex development and germ layer differentiation. We identify a methylation site which impacts neuronal differentiation. Modulation of its methylation levels affects ribosome association of the Fragile X Mental Retardation Protein and translation of WNT pathway-related mRNAs. Together, the data reveals ribosome heterogeneity through rRNA 2-O-methylation during early development and differentiation and suggests a direct role for ribosomes in regulating translation during cell fate acquisition.

developmental biology↗

bioRxiv2021

Spatial-proteomics reveal in-vivo phospho-signaling dynamics at subcellular resolution

Dynamic change in subcellular localization of signaling proteins is a general concept that eukaryotic cells evolved for eliciting a coordinated response to stimuli. Mass spectrometry (MS)-based proteomics in combination with subcellular fractionation can provide comprehensive maps of spatio-temporal regulation of cells, but involves laborious workflows that does not cover the phospho-proteome level. Here we present a high-throughput workflow based on sequential cell fractionation to profile the global proteome and phospho-proteome dynamics across six distinct subcellular fractions. We benchmarked the workflow by studying spatio-temporal EGFR phospho-signaling dynamics in-vitro in HeLa cells and in-vivo in mouse tissues. Finally, we investigated the spatio-temporal stress signaling, revealing cellular relocation of ribosomal proteins in response to hypertonicity and muscle contraction. Proteomics data generated in this study can be explored through https://SpatialProteoDynamics.github.io.

systems biology↗

bioRxiv2019

RRP7A links primary microcephaly to radial glial cells and dysfunction of ribosomal biogenesis, neurogenesis and ciliary resorption

Introductory paragraphPrimary microcephaly (MCPH) is characterized by reduced brain size and intellectual disability1. The exact pathophysiological mechanism underlying MCPH remains to be elucidated, but dysfunction of neuronal progenitors in the developing neocortex plays a major role1. Using homozygosity mapping and whole exome sequencing, we identified a homozygous missense mutation (p.W155C) in Ribosomal RNA Processing 7 Homolog A, RRP7A, which segregated with MCPH in a consanguineous family with 10 affected individuals. RRP7A is expressed in neural stem cells/radial glial cells of the developing human forebrain, and targeted mutation of Rrp7a leads to defects in both neurogenesis and proliferation in a mouse stem cell model. RRP7A localizes to centrosomes, cilia and nucleoli, and patient-derived fibroblasts display defects in processing of ribosomal RNA, resorption of primary cilia and cell cycle progression. Finally, analysis of zebrafish embryos with loss-of-function mutation in rrp7a confirmed that RRP7A depletion causes reduced brain size, impaired neurogenesis and cell proliferation as well as defective ribosomal RNA processing. These findings provide novel insight into human brain development and MCPH.

neuroscience↗