INVESTIGADORES
MONTANARO Mauro Aldo
congresos y reuniones científicas
Título:
Mitochondrial GPAT1 Is Most Active In OMM but Not In Mitochoncrial Associated Vesicles (MAV)
Autor/es:
PELLON MAISON M; MONTANARO MA; COLEMAN RA; GONZALEZ-BARÓ MR
Lugar:
Rosario, Argentina
Reunión:
Congreso; XLII Anual Meeting of SAIB (Sociedad Argentina de Bioquimica y Biologia Molecular); 2006
Resumen:
MITOCHONDRIAL GPAT1 IS MOST ACTIVE IN OMM
BUT NOT IN MITOCHONDRIAL ASSOCIATED
VESICLES (MAV)
Pellon Maison, Magalí*; Montanaro, Mauro*; Coleman, Rosalind
A.#; Gonzalez-Baro, María R.*
*INIBIOLP, 60 & 120, 1900, La Plata, Argentina; and #Dept. of
Nutrition, UNC, Chapel Hill, NC. mgbaro@atlas.med.unlp.edu.ar
Glycerol 3-phosphate acyltransferase-1 (GPAT1), catalyzes the
committed step in glycerolipid synthesis. Both GPAT1 and
carnitine-palmitoyltransferase 1 (CPT1) are located on the outer
mitochondrial membrane (OMM) and their reciprocal regulation
may control acyl-CoA metabolism at the OMM.
To determine whether GPAT1, like CPT1, is enriched in both
mitochondrial contact sites (CS) and OMM, and to correlate
protein location and enzymatic function, we obtained rat liver
submitochondrial fractions. Most GPAT1 protein was present in a
vesicular fraction associated with mitochondria (MAV) but GPAT
specific activity in this fraction was low. In contrast, highest
GPAT1 specific activity was present in OMM from purified
mitochondria. Contact sites from crude mitochondria (ER-CS)
also showed high GPAT1 expression but low specific activity.
To determine how GPAT1 is targeted to mitochondria,
recombinant protein was synthesized in vitro and its
incorporation into crude and purified mitochondria was assayed.
GPAT1 was rapidly incorporated into mitochondria, but not into
microsomes. Incorporation was ATP-driven and GPAT1 became
an integral membrane protein after incorporation. These results
demonstrate that two pools of GPAT1 are present in rat liver
mitochondria: an active one, located in OMM and a less active
one, located in membranes (ER-CS and MAV) associated with
both mitochondria and ER