Energy-coupling in adrenal chromaffin granules

Bashford, C. L.; Casey, Robert P.; Radda, George K.; Ritchie, Gillian A.

doi:10.1016/0306-4522(76)90133-0

Cited by 132 publications

(54 citation statements)

References 49 publications

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“…When a potassium gradient was imposed in the absence of nigericin, small but significant uptake of epinephrine was observed (Fig. 3) (20). As shown in Fig.…”

mentioning

confidence: 81%

Role of a transmembrane pH gradient in epinephrine transport by chromaffin granule membrane vesicles.

Schuldiner¹,

Fishkes²,

Kanner³

1978

Proc. Natl. Acad. Sci. U.S.A.

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ABSTRACr ATP-driven transport and accumulation of epinepbrine in chromaffin granule membrane vesicles isolated from vine adrenal medulla is inhibited by the proton ionophores carbonylcyanide p-trifluoromethoxyphenylhydrazone and nigercin, but not by valinomycin. Moreover, an artificially imposed pH gradient (interior acid) is able to drive this reserpine-sensitie tran rt system in the absence of ATP. Diacan inactivator of the chromaffin granye membrane-bound ATPase, completely inhibits ATP-dependent epinephrine accumulation, but has much less effect when an imposed pH gradient is the driving force for epinephrine transport. The findings provide a strong indication that a pH gradient (interior acid) is the immediate driving force for epinephrine uptake in these storage granules and suggest that ATP-driven epinephrine transport is the result of two processes: (i) generation of a proton electrochemical gradient (interior acid and positive) by the membrane-bound, proton-translocating ATPase; and (ii) pH gradient-driven accumulation of the catecholamine.Chromaffin granules concentrate, store, and release most of the catecholamines in the adrenal medulla (1-4). Isolated granules catalyze ATP-dependent uptake of massive amounts of epinephrine (5, 6), and the process is inhibited by proton conductors (7). ATPase activity (8-11), ATP-dependent proton translocation (12), and ATP-dependent changes in the fluorescence of 1-anilino naphthalene-8-sulfonate (ANS) (11) have been detected in intact granules or membrane vesicles prepared from chromaffin granules by osmotic shock. Moreover, it has been demonstrated that an uncoupler-sensitive pH gradient (ApH, interior acid) is maintained across the chromaffin granule membrane (13-15). These findings have led to the proposal that the membrane-bound ATPase in chromaffin granules is a proton-translocating enzyme that generates a proton electrochemical gradient (interior acid and positive) and that the low internal pH may have a dual role in the mechanism of catecholamine uptake and storage: (i) it may provide the driving force for catecholamine accumulation (putatively, the catecholamine is translocated across the membrane in its unprotonated form and accumulation results from protonation in the intragranular space); and (Ui) it may prevent oxidation of intragranular catecholamines.In this communication, we demonstrate that imposition of a ApH (interior acid) across the membrane of isolated chromaffin granule membrane vesicles induces the accumulation of epinephrine by a transport system that is inhibited by reserpine. This phenomenon is independent of ATP, relatively mildly inhibited by dicyclohexylcarbodiimide (DCCD), an inactivator of the membrane-bound ATPase, and markedly inhibited by carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP) and nigericin. The findings support the contention that ATP hydrolysis in chromaffin granules leads to the generation of a ApH (interior acid) that provides the immediate driving force for epinephrine accumulation.MATERIALS AND METHODS Prepa...

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“…When a potassium gradient was imposed in the absence of nigericin, small but significant uptake of epinephrine was observed (Fig. 3) (20). As shown in Fig.…”

mentioning

confidence: 81%

Role of a transmembrane pH gradient in epinephrine transport by chromaffin granule membrane vesicles.

Schuldiner¹,

Fishkes²,

Kanner³

1978

Proc. Natl. Acad. Sci. U.S.A.

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“…To exc1ude the possibility that Ca2+ uptake is supported by endogenous (leaked out) ATP, we have used known inhibitors of the adrenal medullary secretory vesic1es Mg 2+ -ATPase (F), N-ethylmaleimide (11), and of the Fa-protein (the proton translocating part), dicyc1ohexylcarbodii-mide [12]. Neither of the two substances was effective in inhibiting the uptake of Ca2+ (Table I).…”

Section: --I ------I F ----+ --_ + ---Tmentioning

confidence: 99%

Uptake of Ca2+ by isolated secretory vesicles from adrenal medulla

Krieger-Brauer

Gratzl

1982

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…Dicyclohexylcarbodiimide,which is thought to act in mitochondria By blocking the proton conducting channel [2B ,221 inhibits Pbe reconstituted chromafik granule ATPase as it does in the native membrane [2].…”

Section: Discussionmentioning

confidence: 99%

Reconstitution of the Mg²⁺‐ATPase of the chromaffin granule membrane

1979

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It has been demonstrated that the Mg"-dependent ATPase of the adrenomedullary storage vesicles dchromaffin granuies) is an inwardly directed electrogenic proton pump [14]. The active accumulation of catecholamines is dependent on ATP-linked proton transiocation [7] and it appears that both the pH gradient [8,9j and [15,16] imply that a study of this system does not only help in elucidating the mechanism of neurotransmitter storage but may also lead p.o a general understanding of how ATP hydrolysis generates a proton gradient.Any detailed molecular analysis of the reaction requires simplification of the system and in this paper After stirring at 4'C for 2Q min the suspension was centrifuged at 100 000 X gait in an MSE Prepspin centrifuge for 1 h. The supernatant (cholate extract) was decanted from th.e pellet and kept at 4OC until USC?.Del.ipidation x&as carried out by dropwise addition

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Energy-coupling in adrenal chromaffin granules

Cited by 132 publications

References 49 publications

Role of a transmembrane pH gradient in epinephrine transport by chromaffin granule membrane vesicles.

Role of a transmembrane pH gradient in epinephrine transport by chromaffin granule membrane vesicles.

Uptake of Ca2+ by isolated secretory vesicles from adrenal medulla

Reconstitution of the Mg²⁺‐ATPase of the chromaffin granule membrane

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Energy-coupling in adrenal chromaffin granules

Cited by 132 publications

References 49 publications

Role of a transmembrane pH gradient in epinephrine transport by chromaffin granule membrane vesicles.

Role of a transmembrane pH gradient in epinephrine transport by chromaffin granule membrane vesicles.

Uptake of Ca2+ by isolated secretory vesicles from adrenal medulla

Reconstitution of the Mg2+‐ATPase of the chromaffin granule membrane

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Reconstitution of the Mg²⁺‐ATPase of the chromaffin granule membrane