Jingchuan Luo
@jingchuanluo.bsky.social
(16) In summary, a majority of mitochondrial proteins are imported post-translationally. A subset uses localized translation. Long proteins are cotranslationally targeted by a bipartite signal. Short proteins, however, use translation-independent mRNA targeting mediated by AKAP1.
August 27, 2025 at 9:44 PM
(16) In summary, a majority of mitochondrial proteins are imported post-translationally. A subset uses localized translation. Long proteins are cotranslationally targeted by a bipartite signal. Short proteins, however, use translation-independent mRNA targeting mediated by AKAP1.
(15) Localized translation of long proteins is conserved in yeast, unlike that of short proteins. As these proteins often originate from prokaryotes, this suggests that localized translation is an ancient mechanism that ensures their proper synthesis and mitochondrial import.
August 27, 2025 at 9:44 PM
(15) Localized translation of long proteins is conserved in yeast, unlike that of short proteins. As these proteins often originate from prokaryotes, this suggests that localized translation is an ancient mechanism that ensures their proper synthesis and mitochondrial import.
(14) In AKAP1 null mutants, oxidative phosphorylation (OXPHOS) components are significantly reduced, suggesting that localized translation may represent a novel regulatory mechanism for OXPHOS, as electron transport chain (ETC) subunits are highly enriched in this pathway.
August 27, 2025 at 9:44 PM
(14) In AKAP1 null mutants, oxidative phosphorylation (OXPHOS) components are significantly reduced, suggesting that localized translation may represent a novel regulatory mechanism for OXPHOS, as electron transport chain (ETC) subunits are highly enriched in this pathway.
(13) AKAP1’s ability to recruit mRNAs correlates with its ability to mediate local translation, revealed by RIP-qPCR experiments with different AKAP1 variants and short CDS mutant reporters, supporting the idea that AKAP1 directly interacts with RNA to recruit the short CDS.
August 27, 2025 at 9:44 PM
(13) AKAP1’s ability to recruit mRNAs correlates with its ability to mediate local translation, revealed by RIP-qPCR experiments with different AKAP1 variants and short CDS mutant reporters, supporting the idea that AKAP1 directly interacts with RNA to recruit the short CDS.
(12) We found that the mitochondrial outer membrane protein AKAP1 mediates the recruitment of short CDS transcripts through its KH domain and Tudor domains, but not its PKA-helix.
August 27, 2025 at 9:44 PM
(12) We found that the mitochondrial outer membrane protein AKAP1 mediates the recruitment of short CDS transcripts through its KH domain and Tudor domains, but not its PKA-helix.
(11) However, local recruitment of short CDS transcripts (e.g. NDUFB9) is uncoupled from protein import, which requires a functional MTS.
August 27, 2025 at 9:44 PM
(11) However, local recruitment of short CDS transcripts (e.g. NDUFB9) is uncoupled from protein import, which requires a functional MTS.
(10) Localized recruitment of short proteins is mediated by RNA, independent of the MTS and protein translation. A synthetic reporter with the UTRs from the COX7A2 gene (one of the top hits), a single intron, and a partial mCherry sequence was sufficient for recruitment.
August 27, 2025 at 9:44 PM
(10) Localized recruitment of short proteins is mediated by RNA, independent of the MTS and protein translation. A synthetic reporter with the UTRs from the COX7A2 gene (one of the top hits), a single intron, and a partial mCherry sequence was sufficient for recruitment.
(9) We found that cells prevent the cotranslational import of most mitochondrial proteins with an inhibitory signal. In contrast, long proteins are recruited cotranslationally by a bipartite signal: an MTS and a downstream region (100-350aa) that lacks the inhibitory signal.
August 27, 2025 at 9:44 PM
(9) We found that cells prevent the cotranslational import of most mitochondrial proteins with an inhibitory signal. In contrast, long proteins are recruited cotranslationally by a bipartite signal: an MTS and a downstream region (100-350aa) that lacks the inhibitory signal.
(8) There are distinct mechanisms for each group. Long proteins initiate synthesis in the cytosol, and through co-translational recruitment, finish at the mitochondria. In contrast, short protein mRNAs are recruited to the mitochondria before translation begins.
August 27, 2025 at 9:44 PM
(8) There are distinct mechanisms for each group. Long proteins initiate synthesis in the cytosol, and through co-translational recruitment, finish at the mitochondria. In contrast, short protein mRNAs are recruited to the mitochondria before translation begins.
(7) We found that ~20% of nuclear-encoded mitochondrial proteins are translated locally at mitochondria. These fall into two groups by length: long proteins (>400aa), enriched in matrix metabolic enzymes, and short proteins (<200aa), enriched in electron transport chain subunits.
August 27, 2025 at 9:44 PM
(7) We found that ~20% of nuclear-encoded mitochondrial proteins are translated locally at mitochondria. These fall into two groups by length: long proteins (>400aa), enriched in matrix metabolic enzymes, and short proteins (<200aa), enriched in electron transport chain subunits.
(6) We next applied LOCL-TL to identify genes translated at the mitochondria. Our method demonstrated high specificity, as 99% of our positive mitochondrial transcripts were also found in the mito APEX-seq dataset (sciencedirect.com/science/arti...), which labels mRNA near mitochondria.
August 27, 2025 at 9:44 PM
(6) We next applied LOCL-TL to identify genes translated at the mitochondria. Our method demonstrated high specificity, as 99% of our positive mitochondrial transcripts were also found in the mito APEX-seq dataset (sciencedirect.com/science/arti...), which labels mRNA near mitochondria.
(5) We benchmarked LOCL-TL in the ER system, where it robustly enriched for secretory proteins known to be translated locally at the ER membrane.
August 27, 2025 at 9:44 PM
(5) We benchmarked LOCL-TL in the ER system, where it robustly enriched for secretory proteins known to be translated locally at the ER membrane.
(4) To solve this, we collaborated with @aliceyting.bsky.social Song-Yi Lee to develop an optogenetic tool, the LOV-domain Controlled Ligase for Translation Localization (LOCL-TL), to label and pull down locally translated ribosomes for ribosome profiling under normal growth conditions.
August 27, 2025 at 9:44 PM
(4) To solve this, we collaborated with @aliceyting.bsky.social Song-Yi Lee to develop an optogenetic tool, the LOV-domain Controlled Ligase for Translation Localization (LOCL-TL), to label and pull down locally translated ribosomes for ribosome profiling under normal growth conditions.
(3) A decade ago, our lab developed proximity-specific ribosome profiling (science.org/doi/10.1126/...) to quantitatively monitor localized translation. However, this method requires cells to grow in biotin-depleted media, which causes a strong mitochondrial and cell-growth defect.
August 27, 2025 at 9:44 PM
(3) A decade ago, our lab developed proximity-specific ribosome profiling (science.org/doi/10.1126/...) to quantitatively monitor localized translation. However, this method requires cells to grow in biotin-depleted media, which causes a strong mitochondrial and cell-growth defect.
I'm thrilled to share our work from @weissmanlab.bsky.social (www.sciencedirect.com/science/arti...). We developed LOCL-TL, an optogenetic approach for monitoring localized translation in mammalian cells. LOCL-TL revealed two distinct strategies for mitochondrially localized translation.
August 27, 2025 at 9:44 PM
I'm thrilled to share our work from @weissmanlab.bsky.social (www.sciencedirect.com/science/arti...). We developed LOCL-TL, an optogenetic approach for monitoring localized translation in mammalian cells. LOCL-TL revealed two distinct strategies for mitochondrially localized translation.
(16) In summary, a majority of mitochondrial proteins are imported post-translationally. A subset uses localized translation. Long proteins are cotranslationally targeted by a bipartite signal. Short proteins, however, use translation-independent mRNA targeting mediated by AKAP1.
August 27, 2025 at 9:29 PM
(16) In summary, a majority of mitochondrial proteins are imported post-translationally. A subset uses localized translation. Long proteins are cotranslationally targeted by a bipartite signal. Short proteins, however, use translation-independent mRNA targeting mediated by AKAP1.
(15) Localized translation of long proteins is conserved in yeast, unlike that of short proteins. As these proteins often originate from prokaryotes, this suggests that localized translation is an ancient mechanism that ensures their proper synthesis and mitochondrial import.
August 27, 2025 at 9:29 PM
(15) Localized translation of long proteins is conserved in yeast, unlike that of short proteins. As these proteins often originate from prokaryotes, this suggests that localized translation is an ancient mechanism that ensures their proper synthesis and mitochondrial import.
(14) In AKAP1 null mutants, oxidative phosphorylation (OXPHOS) components are significantly reduced, suggesting that localized translation may represent a novel regulatory mechanism for OXPHOS, as electron transport chain (ETC) subunits are highly enriched in this pathway.
August 27, 2025 at 9:29 PM
(14) In AKAP1 null mutants, oxidative phosphorylation (OXPHOS) components are significantly reduced, suggesting that localized translation may represent a novel regulatory mechanism for OXPHOS, as electron transport chain (ETC) subunits are highly enriched in this pathway.
(13) AKAP1’s ability to recruit mRNAs correlates with its ability to mediate local translation, revealed by RIP-seq experiments with different AKAP1 variants and short CDS mutant reporters, supporting the idea that AKAP1 directly interacts with RNA to recruit the short CDS.
August 27, 2025 at 9:29 PM
(13) AKAP1’s ability to recruit mRNAs correlates with its ability to mediate local translation, revealed by RIP-seq experiments with different AKAP1 variants and short CDS mutant reporters, supporting the idea that AKAP1 directly interacts with RNA to recruit the short CDS.
(12) We found that the mitochondrial outer membrane protein AKAP1 mediates the recruitment of short CDS transcripts through its KH domain and Tudor domains, but not its PKA-helix.
August 27, 2025 at 9:29 PM
(12) We found that the mitochondrial outer membrane protein AKAP1 mediates the recruitment of short CDS transcripts through its KH domain and Tudor domains, but not its PKA-helix.
(11) However, local recruitment of short CDS transcripts (e.g. NDUFB9) is uncoupled from protein import, which requires a functional MTS.
August 27, 2025 at 9:29 PM
(11) However, local recruitment of short CDS transcripts (e.g. NDUFB9) is uncoupled from protein import, which requires a functional MTS.
(10) Localized recruitment of short proteins is mediated by RNA, independent of the MTS and protein translation. A synthetic reporter with the UTRs from the COX7A2 gene (one of the top hits), a single intron, and a partial mCherry sequence was sufficient for recruitment.
August 27, 2025 at 9:29 PM
(10) Localized recruitment of short proteins is mediated by RNA, independent of the MTS and protein translation. A synthetic reporter with the UTRs from the COX7A2 gene (one of the top hits), a single intron, and a partial mCherry sequence was sufficient for recruitment.