Translation rate underpins specific targeting of N-terminal transmembrane proteins to mitochondria  

作　　者：Junho Lee Byeongho Moon Dong Wook Lee Inhwan Hwang 

机构地区：[1]Department of Life Science,Pohang University of Science and Technology,Pohang 790-784,South Korea [2]Department of Integrative Food,Bioscience and Biotechnology,Chonnam National University,Gwangju 61186,South Korea [3]Department Bioenergy Science and Technology,Chonnam National University,Gwangju 61186,South Korea

出　　处：《Journal of Integrative Plant Biology》2023年第6期1505-1520,共16页植物学报（英文版）

基　　金：supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2022R1A2C1091844)。

摘　　要：Protein biogenesis is a complex process,and complexity is greatly increased in eukaryotic cells through specific targeting of proteins to different organelles.To direct targeting,organellar proteins carry an organelle-specific targeting signal for recognition by organelle-specific import machinery.However,the situation is confusing for transmembrane domain(TMD)-containing signalanchored(SA)proteins of various organelles because TMDs function as an endoplasmic reticulum(ER)targeting signal.Although ER targeting of SA proteins is well understood,how they are targeted to mitochondria and chloroplasts remains elusive.Here,we investigated how the targeting specificity of SA proteins is determined for specific targeting to mitochondria and chloroplasts.Mitochondrial targeting requires multiple motifs around and within TMDs:a basic residue and an arginine-rich region flanking the N-and C-termini of TMDs,respectively,and an aromatic residue in the C-terminal side of the TMD that specify mitochondrial targeting in an additive manner.These motifs play a role in slowing down the elongation speed during translation,thereby ensuring mitochondrial targeting in a cotranslational manner.By contrast,the absence of any of these motifs individually or together causes at varying degrees chloroplast targeting that occurs in a post-translational manner.

关 键 词：arginine-rich region ER targeting mitochondria targeting organelle targeting TMD translational slowdown transmembrane domain 

分 类 号：Q75[生物学—分子生物学]