Subcellular localization of VDAC in mitochondria and ER in the cerebellum.
The voltage-dependent anion channel (VDAC) provides passage for adenine nucleotides, Ca2+ and other metabolites into and from mitochondria. Here, the intracellular localization and oligomeric organization of VDAC in brain mitochondria and ER are demonstrated. Immunohistochemical staining of VDAC in rat cerebellum showed high labeling of the Purkinje neurons. Immunogold labeling and EM analysis of the cerebellar molecular layer showed specific VDAC immunostaining of the mitochondrial outer membrane, highly enhanced in contact sites between mitochondria or between mitochondria and associated ER. Purified ER membranes contain VDAC, but not other mitochondrial proteins. Chemical cross-linking of isolated mitochondria, ER or purified VDAC demonstrated the existence of VDAC in oligomeric form. Based on the enrichment of VDAC in the junctional face of closely associated mitochondrial and ER membranes and the existence of VDAC oligomers, we propose an involvement of VDAC in specialized intermembrane communication between mitochondria or between ER and mitochondria, serving to complement the tight structural and functional coupling observed between these organelles.
Shoshan-Barmatz
Varda
V
Department of Life Sciences and Zlotowski Center for Neuroscience, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105, Israel. vardasb@bgumail.bgu.ac.il
Zalk
Ran
R
Gincel
Dan
D
Vardi
Noga
N
D000818:Animals; D002531:Cerebellum / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008928:Mitochondria / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism*
D012333:RNA, Messenger