J Integr Plant Biol. ›› 2017, Vol. 59 ›› Issue (8): 535-551.DOI: 10.1111/jipb.12555

• Cell and Developmental Biology • Previous Articles     Next Articles

HP30-2, a mitochondrial PRAT protein for import of signal sequence-less precursor proteins in Arabidopsis thaliana

Claudia Rossig1, John Gray2, Oscar Valdes1, Sachin Rustgi3,4, Diter von Wettstein4, Christiane Reinbothe1 and Steffen Reinbothe1*   

  1. 1Laboratory of Plant Molecular Genetics and Laboratory of Environmental and Systems Biology, Grenoble-Alpes-University, Grenoble, France
    2Department of Biological Sciences, University of Toledo, Toledo, OH 43606, USA
    3Department of Plant and Environmental Sciences, Pee Dee Research and Education Center, Clemson University, Florence, SC 29506, USA
    4Department of Crop and Soil Sciences, Washington State University, Pullman WA 99164-6420, USA
  • Received:2017-02-16 Accepted:2017-05-19 Published:2017-05-22
  • About author:*Correspondences: E-mail: Steffen Reinbothe (sreinbot@ujf-grenoble.fr)


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 NH2-terminal presequences, whereas HP30-2's interaction with NDC1 may permit controlling mitochondrial biogenesis and activity.

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