In Vivo Dissection of the Intrinsically Disordered Receptor Domain of Tim23

JOURNAL OF MOLECULAR BIOLOGY

卷:432

Article

Guensel, Umut¹  Paz, Eyal²  Gupta, Ruhita¹  Mathes, Isabella³  Azem, Abdussalam²  Mokranjac, Dejana¹ 

[1] Ludwig Maximilians Univ Munchen, BMC Physiol Chem, Grosshadernerstr 9, D-82152 Martinsried, Germany

[2] Tel Aviv Univ, George S Wise Fac Life Sci, Dept Biochem & Mol Biol, IL-69978 Tel Aviv, Israel

[3] MPI Biochem, D-82152 Martinsried, Germany

关键词: mitochondria;    protein sorting;    protein translocation;    TIM23 complex;    presequence pathway;   

DOI  :  10.1016/j.jmb.2020.03.031

来源: Elsevier

【 摘 要 】

In the intermembrane space (IMS) of mitochondria, the receptor domain of Tim23 has an essential role during translocation of hundreds of different proteins from the cytosol via the TOM and TIM23 complexes in the outer and inner membranes, respectively. This intrinsically disordered domain, which can even extend into the cytosol, was shown, mostly in vitro, to interact with several subunits of the TOM and TIM23 complexes. To obtain molecular understanding of this organizational hub in the IMS, we dissected the IMS domain of Tim23 in vivo. We show that the interaction surface of Tim23 with Tim50 is larger than previously thought and reveal an unexpected interaction of Tim23 with Pam17 in the IMS, impairment of which influences their interaction in the matrix. Furthermore, mutations of two conserved negatively charged residues of Tim23, close to the inner membrane, prevented dimerization of Tim23. The same mutations increased exposure of Tim23 on the mitochondrial surface, whereas dissipation of membrane potential decreased it. Our results reveal an intricate network of Tim23 interactions in the IMS, whose influence is transduced across two mitochondrial membranes, ensuring efficient translocation of proteins into mitochondria. (C) 2020 The Author(s). Published by Elsevier Ltd.

【 授权许可】

Free