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HP30‐2, a mitochondrial PRAT protein for import of signal sequence‐less precursor proteins in Arabidopsis thaliana
Author(s) -
Rossig Claudia,
Gray John,
Valdes Oscar,
Rustgi Sachin,
von Wettstein Diter,
Reinbothe Christiane,
Reinbothe Steffen
Publication year - 2017
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/jipb.12555
Subject(s) - arabidopsis thaliana , chloroplast , mitochondrion , biology , translocase , biochemistry , protein targeting , protein subunit , translocase of the inner membrane , biogenesis , pentatricopeptide repeat , nadh dehydrogenase , signal peptide , inner mitochondrial membrane , mitochondrial carrier , respiratory chain , inner membrane , membrane protein , microbiology and biotechnology , mitochondrial membrane transport protein , arabidopsis , peptide sequence , gene , bacterial outer membrane , membrane , chromosomal translocation , escherichia coli , mutant
Chloroplasts and mitochondria contain a family of putative preprotein and amino acid transporters designated PRAT. Here, we analyzed the role of two previously characterized PRAT protein family members, encoded by At3g49560 (HP30) and At5g24650 (HP30‐2), in planta using a combination of genetic, cell biological and biochemical approaches. Expression studies and green fluorescent protein tagging identified HP30‐2 both in chloroplasts and mitochondria, whereas HP30 was located exclusively in chloroplasts. Biochemical evidence was obtained for an association of mitochondrial HP30‐2 with two distinct protein complexes, one containing the inner membrane translocase TIM22 and the other containing an alternative NAD(P)H dehydrogenase subunit (NDC1) implicated in a respiratory complex 1‐like electron transport chain. Through its association with TIM22, HP30‐2 is involved in the uptake of carrier proteins and other, hydrophobic membrane proteins lacking cleavable NH 2 ‐terminal presequences, whereas HP30‐2's interaction with NDC1 may permit controlling mitochondrial biogenesis and activity.