Superresolution Imaging Identifies That Conventional Trafficking Pathways Are Not Essential for Endoplasmic Reticulum to Outer Mitochondrial Membrane Protein Transport.
Most nuclear-encoded mitochondrial proteins traffic from the cytosol to mitochondria. Some of these proteins localize at mitochondria-associated membranes (MAM), where mitochondria are closely apposed with the endoplasmic reticulum (ER). We have previously shown that the human cytomegalovirus signal-anchored protein known as viral mitochondria-localized inhibitor of apoptosis (vMIA) traffics from the ER to mitochondria and clusters at the outer mitochondrial membrane (OMM). Here, we have examined the host pathways by which vMIA traffics from the ER to mitochondria and clusters at the OMM. By disruption of phosphofurin acidic cluster sorting protein 2 (PACS-2), mitofusins (Mfn1/2), and dynamin related protein 1 (Drp1), we find these conventional pathways for ER to the mitochondria trafficking are dispensable for vMIA trafficking to OMM. Instead, mutations in vMIA that change its hydrophobicity alter its trafficking to mitochondria. Superresolution imaging showed that PACS-2- and Mfn-mediated membrane apposition or hydrophobic interactions alter vMIA's ability to organize in nanoscale clusters at the OMM. This shows that signal-anchored MAM proteins can make use of hydrophobic interactions independently of conventional ER-mitochondria pathways to traffic from the ER to mitochondria. Further, vMIA hydrophobic interactions and ER-mitochondria contacts facilitate proper organization of vMIA on the OMM.
Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Ave, NW, Washington, DC, 20010, USA.
Kyle
K
Salka
Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Ave, NW, Washington, DC, 20010, USA.
Shivaprasad
S
Bhuvanendran
Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Ave, NW, Washington, DC, 20010, USA.
Kassandra
K
Wilson
Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Ave, NW, Washington, DC, 20010, USA.|Laboratory of Microbiology, Department of Medicine, School of Health Sciences, University of Ioannina, Ioannina, 45500, Greece.
Petros
P
Bozidis
Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Ave, NW, Washington, DC, 20010, USA.
Mansi
M
Mehta
Section on Biophotonics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, 20892, USA.
Kristin
K
Rainey
Department of Cell Biology, Johns Hopkins University School of Medicine Hunterian 111, 725 N. Wolfe Street, Baltimore, MD, 21205, USA.
Hiromi
H
Sesaki
Section on Biophotonics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, 20892, USA.
George H
GH
Patterson
Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Ave, NW, Washington, DC, 20010, USA. jkjaiswal@childrensnational.org.|Department of Integrative Systems Biology, and of Pediatrics, George Washington University School of Medicine and Health Sciences, Washington, DC, 20037, USA. jkjaiswal@childrensnational.org.
Jyoti K
0000-0002-5992-5185
JK
Jaiswal
Center for Genetic Medicine Research, Children's National Health System, 111 Michigan Ave, NW, Washington, DC, 20010, USA. acolberg-poley@childrensnational.org.|Department of Integrative Systems Biology, and of Pediatrics, George Washington University School of Medicine and Health Sciences, Washington, DC, 20037, USA. acolberg-poley@childrensnational.org.|Departments of Biochemistry & Molecular Medicine, and of Microbiology, Immunology & Tropical Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC, 20037, USA. acolberg-poley@childrensnational.org.
Anamaris M
AM
Colberg-Poley
D000818:Animals; D002478:Cells, Cultured; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D051336:Mitochondrial Membranes / Q000378:metabolism*; D061848:Optical Imaging; D021381:Protein Transport; D015398:Signal Transduction
D017874:Immediate-Early Proteins; D008565:Membrane Proteins; C420323:UL37 protein, Human herpesvirus 5