Transglutaminase activity is present in highly purified nonsynaptosomal mouse brain and liver mitochondria.
Several active transglutaminase (TGase) isoforms are known to be present in human and rodent tissues, at least three of which, namely, TGase 1, TGase 2 (tissue transglutaminase), and TGase 3, are present in the brain. TGase activity is known to be present in the cytosolic, nuclear, and extracellular compartments of the brain. Here, we show that highly purified mouse brain nonsynaptosomal mitochondria and mouse liver mitochondria and mitoplast fractions derived from these preparations possess TGase activity. Western blotting and experiments with TGase 2 knock-out (KO) mice ruled out the possibility that most of the mitochondrial/mitoplast TGase activity is due to TGase 2, the TGase isoform responsible for the majority of the activity ([14C]putrescine-binding assay) in whole brain and liver homogenates. The identity of the mitochondrial/mitoplast TGase(s) is not yet known. Possibly, the activity may be due to one of the other TGase isoforms or perhaps to a protein that does not belong to the classical TGase family. This activity may play a role in regulation of mitochondrial function both in normal physiology and in disease. Its nature and regulation deserve further study.
Krasnikov
Boris F
BF
Department of Neurology and Neurosciences, and Medicine, Weill Medical College of Cornell University, New York City, New York 10021, USA.
Kim
Soo-Youl
SY
McConoughey
Stephen J
SJ
Ryu
Hoon
H
Xu
Hui
H
Stavrovskaya
Irina
I
Iismaa
Siiri E
SE
Mearns
Bryony M
BM
Ratan
Rajiv R
RR
Blass
John P
JP
Gibson
Gary E
GE
Cooper
Arthur J L
AJ
D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology*; D002103:Cadaverine / Q000378:metabolism; D002118:Calcium / Q000502:physiology; D002250:Carbon Radioisotopes / Q000378:metabolism; D002364:Caseins / Q000378:metabolism; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D019793:Fluorescein / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D006168:Guinea Pigs; D007106:Immune Sera / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D018345:Mice, Knockout; D008930:Mitochondria, Liver / Q000201:enzymology*; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011700:Putrescine / Q000378:metabolism; D011869:Radioligand Assay; D013367:Submitochondrial Particles / Q000201:enzymology; D011503:Transglutaminases / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism*
D002250:Carbon Radioisotopes; D002364:Caseins; D007106:Immune Sera; C002087:N,N-dimethylcasein; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins; D002103:Cadaverine; D002118:Calcium; D019793:Fluorescein; D011700:Putrescine