scholarly journals The specific binding of the microtubule-associated protein 2 (MAP2) to the outer membrane of rat brain mitochondria

1989 ◽  
Vol 262 (3) ◽  
pp. 1003-1003
Keyword(s):  
Rat Brain ◽  
Outer Membrane ◽  
Specific Binding ◽  
Brain Mitochondria ◽  
Rat Brain Mitochondria

scholarly journals The specific binding of the microtubule-associated protein 2 (MAP2) to the outer membrane of rat brain mitochondria

1989 ◽  
Vol 261 (1) ◽  
pp. 167-173 ◽  
Author(s):  
M Lindén ◽  
B D Nelson ◽  
J F Leterrier
Keyword(s):  
Rat Brain ◽  
Outer Membrane ◽  
Binding Sites ◽  
Specific Binding ◽  
Brain Mitochondria ◽  
Microtubule Associated Proteins ◽  
Cross Linkage ◽  
Associated Proteins ◽  
A Site

Purified mitochondria from rat brain contain microtubule-associated proteins (MAPs) bound to the outer membrane. Studies of binding in vitro performed with microtubules and with purified microtubule proteins showed that mitochondria preferentially interact with the high-molecular-mass MAPs (and not with Tau protein). Incubation of intact mitochondria with Taxol-stabilized microtubules resulted in the selective trapping of both MAPs 1 and 2 on mitochondria, indicating that an interaction between the two organelles occurred through a site on the arm-like projection of MAPs. Two MAP-binding sites were located on intact mitochondria. The lower-affinity MAP2-binding site (Kd = 2 x 10(-7) M) was preserved and enriched in the outer-membrane fraction, whereas the higher-affinity site (Kd = 1 x 10(-9) M) was destroyed after removing the outer membrane with digitonin. Detergent fractionation of mitochondrial outer membranes saturated with MAP2 bound in vitro showed that MAPs are associated with membrane fragments which contain the pore-forming protein (porin). MAP2 also partially prevents the solubilization of porin from outer membrane, indicating a MAP-induced change in the membrane environment of porin. These observations demonstrate the presence of specific MAP-binding sites on the outer membrane, suggesting an association between porin and the membrane domain involved in the cross-linkage between microtubules and mitochondria.

Subfractionation of the outer membrane of rat brain mitochondria: Evidence for the existence of a domain containing the porin-hexokinase complex

1987 ◽  
Vol 252 (1) ◽  
pp. 188-196 ◽  
Author(s):  
Latifa Dorbani ◽  
Veronika Jancsik ◽  
Monica Linden ◽  
J.François Leterrier ◽  
B.Dean Nelson ◽  
...  
Keyword(s):  
Rat Brain ◽  
Outer Membrane ◽  
Brain Mitochondria ◽  
Rat Brain Mitochondria

Acyl-CoA: sn-Glycerol-3-Phosphate O-Acyltransferase in Rat Brain Mitochondria and Microsomes

1982 ◽  
Vol 39 (1) ◽  
pp. 286-289 ◽  
Author(s):  
Susan M. Fitzpatrick ◽  
Giovanna Sorresso ◽  
Dipak Haldar
Keyword(s):  
Rat Brain ◽  
Brain Mitochondria ◽  
Rat Brain Mitochondria

scholarly journals The role of ADP in the modulation of the calcium-efflux pathway in rat brain mitochondria

1985 ◽  
Vol 225 (1) ◽  
pp. 41-49 ◽  
Author(s):  
J Vitorica ◽  
J Satrústegui
Keyword(s):  
Rat Brain ◽  
Binding Sites ◽  
Tricarboxylic Acid Cycle ◽  
Brain Mitochondria ◽  
Ruthenium Red ◽  
Calcium Efflux ◽  
Rat Brain Mitochondria ◽  
Pi Complex ◽  
Efflux Pathway

The role of ADP in the regulation of Ca2+ efflux in rat brain mitochondria was investigated. ADP was shown to inhibit Ruthenium-Red-insensitive H+- and Na+-dependent Ca2+-efflux rates if Pi was present, but had no effect in the absence of Pi. The primary effect of ADP is an inhibition of Pi efflux, and therefore it allows the formation of a matrix Ca2+-Pi complex at concentrations above 0.2 mM-Pi and 25 nmol of Ca2+/mg of protein, which maintains a constant free matrix Ca2+ concentration. ADP inhibition of Pi and Ca2+ efflux is nucleotide-specific, since in the presence of oligomycin and an inhibitor of adenylate kinase ATP does not substitute for ADP, is dependent on the amount of ADP present, and requires ADP concentrations in excess of the concentrations of translocase binding sites. Brain mitochondria incubated with 0.2 mM-Pi and ADP showed Ca2+-efflux rates dependent on Ca2+ loads at Ca2+ concentrations below those required for the formation of a Pi-Ca2+ complex, and behaved as perfect cytosolic buffers exclusively at high Ca2+ loads. The possible role of brain mitochondrial Ca2+ in the regulation of the tricarboxylic acid-cycle enzymes and in buffering cytosolic Ca2+ is discussed.

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