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Functional expression of V‐ATPases in the plasma membrane of glial cells
Author(s) -
Philippe JeanMarc,
Dubois JeanMarc,
RouzaireDubois Beatrice,
Cartron PierreFrançois,
Vallette François,
Morel Nicolas
Publication year - 2002
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.10041
Subject(s) - biology , bafilomycin , endocytosis , microbiology and biotechnology , v atpase , atpase , intracellular , neuroglia , glioma , cell culture , cell , biochemistry , central nervous system , enzyme , endocrinology , cancer research , apoptosis , autophagy , genetics
Abstract Vacuolar H + ATPase (V‐ATPase) activity is essential for many cellular processes, including intracellular membrane traffic, protein processing and degradation, and receptor‐mediated endocytosis. Proton transport by V‐ATPases could also play a role during cell transformation, tumorigenesis, and cell metastasis, and V‐ATPase c‐subunit overexpression was reported to be correlated with invasiveness of pancreatic tumors (Ohta et al., 1996). In the present work, we found that mRNAs encoding V‐ATPase subunits are not overexpressed in C6 tumoral glioma cells when compared with immortalized astrocytes DI TNC1 and astrocytes in primary cultures. Accordingly, V‐ATPase subunit mRNA levels are similar in human gliomas (grade II or IV) and in peritumoral tissues. A significant proportion (25%) of V‐ATPase is present in the plasma membrane of both the C6 and the DI TNC1 astrocytic cells in culture. A bafilomycin‐sensitive hyperpolarizing pump current through the plasma membrane was detected and measured after ionic channel inhibition, which corresponds most probably to an electrogenic transport of protons. This suggests that the plasma membrane V‐ATPase is active. It could contribute to cytoplasmic pH regulation in astrocytic cells. GLIA 37:365–373, 2002. © 2002 Wiley‐Liss, Inc.