Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Mechanisms of pH regulation in the regulated secretory pathway
Autore:
Wu, MM; Grabe, M; Adams, S; Tsien, RY; Moore, HPH; Machen, TE;
Indirizzi:
Univ Calif Berkeley, Dept Cell & Mol Biol, Berkeley, CA 94720 USA Univ Calif Berkeley Berkeley CA USA 94720 ol Biol, Berkeley, CA 94720 USA Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA Univ Calif Berkeley Berkeley CA USA 94720 pt Phys, Berkeley, CA 94720 USA Univ Calif San Diego, Dept Pharmacol, La Jolla, CA 92093 USA Univ Calif San Diego La Jolla CA USA 92093 rmacol, La Jolla, CA 92093 USA Univ Calif San Diego, Howard Hughes Med Inst, La Jolla, CA 92093 USA Univ Calif San Diego La Jolla CA USA 92093 d Inst, La Jolla, CA 92093 USA
Titolo Testata:
JOURNAL OF BIOLOGICAL CHEMISTRY
fascicolo: 35, volume: 276, anno: 2001,
pagine: 33027 - 33035
SICI:
0021-9258(20010831)276:35<33027:MOPRIT>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
TRANS-GOLGI NETWORK; GREEN FLUORESCENT PROTEINS; LIVING CELLS; SYNAPTIC VESICLES; SECRETOGRANIN-II; MEMBRANE; ACIDIFICATION; GRANULE; COMPLEX; INSULIN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Machen, TE Univ Calif Berkeley, Dept Cell & Mol Biol, 231 Life Sci Addit, Berkeley, CA 94720 USA Univ Calif Berkeley 231 Life Sci Addit Berkeley CA USA 94720 SA
Citazione:
M.M. Wu et al., "Mechanisms of pH regulation in the regulated secretory pathway", J BIOL CHEM, 276(35), 2001, pp. 33027-33035

Abstract

A precise pH gradient between organelles of the regulated secretory pathway is required for sorting and processing of prohormones. We studied pH regulation in live endocrine cells by targeting biotin-based pH indicators to cellular organelles expressing avidin-chimera proteins. In AtT-20 cells, we found that steady-state pH decreased from the endoplasmic reticulum (ER) (pH(ER) = 7.4 +/- 0.2, mean +/- S.D.) to Golgi (pH(G) = 6.2 +/- 0.4) to mature secretory granules (MSGs) (pH(MSG) = 5.5 +/- 0.4). Golgi and MSGs required active H+ v-ATPases for acidification. ER, Golgi, and MSG steady-state pHvalues were also dependent upon the different H+ leak rates across each membrane. However, neither steady-state pH(MSG) nor rates of passive H+ leak were affected by Cl--free solutions or valinomycin, indicating that MSG membrane potential was small and not a determinant of pH(MSG). Therefore, our data do not support earlier suggestions that organelle acidification is primarily regulated by Cl- conductances. Measurements of H+ leak rates, buffercapacities, and estimates of surface areas and volumes of these organelleswere applied to a mathematical model to determine the H+ permeability (PH+) of each organelle membrane. We found that PH+ decreased progressively from ER to Golgi to MSGs, and proper acidification of Golgi and MSGs required gradual decreases in PH+ and successive increases in the active H+ pump density.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/11/20 alle ore 10:42:13