PMID- 7929102
OWN - NLM
STAT- MEDLINE
DCOM- 19941027
LR  - 20210210
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 269
IP  - 39
DP  - 1994 Sep 30
TI  - Monoclonal antibodies against MDR1 P-glycoprotein inhibit chloride conductance 
      and label a 65-kDa protein in pancreatic zymogen granule membranes.
PG  - 24410-7
AB  - The regulation of Cl- and cation conductances by the nonhydrolyzable ATP analog 
      adenosine 5'-(beta,gamma-methylene)triphosphate (AMP-PCP) was characterized in 
      isolated zymogen granules (ZG) from pancreatic acinar cells. ZG were purified 
      from rat pancreas homogenate by Percoll gradient centrifugation. Cl- conductance 
      was assayed by suspending ZG in isotonic KCl buffer and measuring osmotic lysis 
      induced by maximal permeabilization of ZG membranes (ZGM) for K+ with the K+ 
      ionophore valinomycin (Val). This resulted in influx of K+ through the artificial 
      pathway and of Cl- through endogenous channels. To measure cation conductances ZG 
      (pHi approximately 6) were suspended in pH 7 buffered isotonic monovalent cation 
      acetate salts. The pH gradient was converted into an outside-directed H+ 
      diffusion potential by maximally increasing H+ conductance of ZGM with the 
      protonophore carbonyl cyanide p-chlorophenylhydrazone. Osmotic lysis of ZG was 
      induced by H+ diffusion potential driven influx of monovalent cations through 
      endogenous channels and non-ionic diffusion of the counterion acetate. In the 
      absence of Val, ZG were stable in KCl buffer up to 2 h. AMP-PCP enhanced osmotic 
      lysis approximately 4-fold compared to control, due to activation of Cl- 
      conductance by AMP-PCP and K+ influx through an AMP-PCP-insensitive nonselective 
      cation pathway, which could be blocked by 0.1 mM Ba2+, 0.5 mM quinine, or 0.2 mM 
      flufenamate. In addition, a K+ and Rb+ selective cation conductance was found 
      which was completely blocked by 0.5 mM AMP-PCP or 0.5 mM quinine. AMP-PCP induced 
      Cl- conductance was strongly inhibited by two monoclonal antibodies against MDR1 
      P-glycoprotein (JSB-1 and C219; 5-10 micrograms/ml), but not by a monoclonal 
      antibody against the cystic fibrosis transmembrane conductance regulator (M3A7; 5 
      micrograms/ml) or by mouse IgG. The AMP-PCP insensitive nonselective cation 
      conductance was not blocked by monoclonal antibodies against MDR1 P-glycoprotein 
      (MDR1). Immunoblot studies of ZG membranes revealed the presence of a major 
      immunoreactive protein band of approximately 65 kDa with both monoclonal 
      antibodies against MDR1, but no protein of the approximate size of MDR1 
      (approximately 170 kDa) was detected. We propose that the Cl- channel or a 
      regulator of the channel, that is activated by the non-hydrolyzable ATP analog 
      AMP-PCP in ZG membranes, is a member of the ATP binding cassette superfamily of 
      transporters and may have homology to MDR1 P-glycoprotein.
FAU - Thevenod, F
AU  - Thevenod F
AD  - II. Department of Physiology, Medical Faculty, University of Saarland, 
      Hamburg/Saar, Federal Republic of Germany.
FAU - Anderie, I
AU  - Anderie I
FAU - Schulz, I
AU  - Schulz I
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (ATP Binding Cassette Transporter, Subfamily B, Member 1)
RN  - 0 (Antibodies, Monoclonal)
RN  - 0 (Chloride Channels)
RN  - 0 (Chlorides)
RN  - 0 (Enzyme Precursors)
RN  - 2001-95-8 (Valinomycin)
RN  - 3469-78-1 (5'-adenylyl (beta,gamma-methylene)diphosphonate)
RN  - 8L70Q75FXE (Adenosine Triphosphate)
RN  - NYX13NT29D (alpha,beta-methyleneadenosine 5'-triphosphate)
RN  - RWP5GA015D (Potassium)
SB  - IM
MH  - ATP Binding Cassette Transporter, Subfamily B, Member 1/*immunology
MH  - Adenosine Triphosphate/analogs & derivatives/metabolism/pharmacology
MH  - Animals
MH  - Antibodies, Monoclonal/*immunology
MH  - Chloride Channels/*antagonists & inhibitors
MH  - Chlorides/metabolism
MH  - Cytoplasmic Granules/metabolism
MH  - Drug Resistance
MH  - Enzyme Precursors/*metabolism
MH  - Hydrolysis
MH  - Intracellular Membranes/metabolism
MH  - Male
MH  - Osmolar Concentration
MH  - Pancreas/*metabolism
MH  - Potassium/metabolism
MH  - Rats
MH  - Rats, Wistar
MH  - Valinomycin/pharmacology
EDAT- 1994/09/30 00:00
MHDA- 1994/09/30 00:01
CRDT- 1994/09/30 00:00
PHST- 1994/09/30 00:00 [pubmed]
PHST- 1994/09/30 00:01 [medline]
PHST- 1994/09/30 00:00 [entrez]
AID - S0021-9258(19)51099-7 [pii]
PST - ppublish
SO  - J Biol Chem. 1994 Sep 30;269(39):24410-7.