TY - JOUR
T1 - Association of a novel mitochondrial protein m19 with mitochondrial nucleoids
AU - Sumitani, Megumi
AU - Kasashima, Katsumi
AU - Ohta, Eriko
AU - Kang, Dongchon
AU - Endo, Hitoshi
N1 - Funding Information:
This work was supported in part by a grant from the Jichi Medical University Young Investigator Award program to K.K.
PY - 2009/11
Y1 - 2009/11
N2 - We have identified a novel mitochondrial protein, termed M19, by proteomic analysis of mitochondrial membrane proteins from HeLa cells. M19 is highly conserved among vertebrates, and possesses no homologous domains with other known proteins. By northern and western blotting, mouse M19 was shown to be expressed in various tissues, and to be especially abundant in the brain. Human M19 (hM19) is present in mitochondria, and protease-protection experiment showed it to be sublocalized in the matrix space. Carboxy-terminally tagged hM19 appeared as spotted signals within mitochondria and co-localized with signals arising from mitochondrial DNA (mtDNA), suggesting the inclusion of M19 in the mtDNAprotein complex (mitochondrial nucleoids). Fractionation of mitochondrial nucleoids from HeLa cells revealed that hM19 has a similar distribution pattern like that of known nucleoid components, such as mtSSB and PHBs, and surely exists in the nucleoid fraction. Furthermore, expression of M19 is closely related to the amount of mtDNA, because it was down-regulated in mtDNA-depleted ρ0 HeLa cells. These results indicate that M19 associates with the nucleoid and likely regulates the organization and metabolism of mtDNA.
AB - We have identified a novel mitochondrial protein, termed M19, by proteomic analysis of mitochondrial membrane proteins from HeLa cells. M19 is highly conserved among vertebrates, and possesses no homologous domains with other known proteins. By northern and western blotting, mouse M19 was shown to be expressed in various tissues, and to be especially abundant in the brain. Human M19 (hM19) is present in mitochondria, and protease-protection experiment showed it to be sublocalized in the matrix space. Carboxy-terminally tagged hM19 appeared as spotted signals within mitochondria and co-localized with signals arising from mitochondrial DNA (mtDNA), suggesting the inclusion of M19 in the mtDNAprotein complex (mitochondrial nucleoids). Fractionation of mitochondrial nucleoids from HeLa cells revealed that hM19 has a similar distribution pattern like that of known nucleoid components, such as mtSSB and PHBs, and surely exists in the nucleoid fraction. Furthermore, expression of M19 is closely related to the amount of mtDNA, because it was down-regulated in mtDNA-depleted ρ0 HeLa cells. These results indicate that M19 associates with the nucleoid and likely regulates the organization and metabolism of mtDNA.
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U2 - 10.1093/jb/mvp118
DO - 10.1093/jb/mvp118
M3 - Article
C2 - 19643811
AN - SCOPUS:70449627527
VL - 146
SP - 725
EP - 732
JO - Journal of Biochemistry
JF - Journal of Biochemistry
SN - 0021-924X
IS - 5
ER -