PMID- 7593238
OWN - NLM
STAT- MEDLINE
DCOM- 19951228
LR  - 20131121
IS  - 0021-9541 (Print)
IS  - 0021-9541 (Linking)
VI  - 165
IP  - 3
DP  - 1995 Dec
TI  - Chemoattractant-induced activation of vacuolar H+ pumps and of an H(+)-selective 
      conductance in neutrophils.
PG  - 588-99
AB  - Upon binding to their receptors on the surface of neutrophils, chemotactic 
      peptides elicit a burst of metabolic activity. The excess acid generated by this 
      burst must be rapidly extruded in order to maintain intracellular pH and preserve 
      normal microbicidal responses. Recently, H(+)-pumping vacuolar-type ATPases 
      (V-pumps) and a H(+)-selective conductance were described in the membrane of 
      neutrophils. However, these systems are virtually quiescent in resting cells. In 
      this report, we analyzed whether the V-pumps and the conductance become active 
      and contribute to pH regulation following cell activation by chemoattractants. 
      Formyl-Met-Leu-Phe (fMLP) was found to stimulate V-pumps, as assessed by the 
      appearance of bafilomycin-sensitive H+ extrusion. Concomitantly, the 
      chemoattractant also activated the H+ conductance, detected as a 
      voltage-dependent and Zn(2+)-sensitive net H+ efflux. In both cases, activation 
      was prevented by treatment with competing antagonistic peptides or with pertussis 
      toxin, implying mediation by a receptor coupled to a heterotrimeric G protein. 
      The signalling pathways downstream of the G proteins were also investigated. 
      Stimulation of neither the V-pump nor the conductance required activation of 
      protein kinase C. An elevation of cytosolic calcium ([Ca2+]i) comparable to that 
      induced by fMLP did not suffice to trigger either transporter. Moreover 
      activation of the conductance remained unaffected when the 
      chemoattractant-induced increase in [Ca2+]i was precluded. In contrast, 
      stimulation of the V-pump was substantially (approximately 50%) depressed when 
      [Ca2+]i was prevented from rising. Tyrosine phosphorylation of several 
      polypeptides accompanies stimulation by fMLP. Prevention of phosphotyrosine 
      accumulation resulted in a pronounced inhibition of H(+)-pumping and of the H+ 
      conductance. Together, these data indicate that engagement of surface receptors 
      by chemotactic peptides can lead to stimulation of two voltage-sensitive pH 
      regulatory pathways, a pump and a conductance, by a pathway that requires 
      tyrosine phosphorylation. Both pathways are capable of sizable H+ extrusion, 
      thereby contributing to pH regulation during the metabolic burst.
FAU - Nanda, A
AU  - Nanda A
AD  - Division of Cell Biology, Hospital for Sick Children, Toronto, Canada.
FAU - Grinstein, S
AU  - Grinstein S
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Cell Physiol
JT  - Journal of cellular physiology
JID - 0050222
RN  - 0 (Chemotactic Factors)
RN  - 0 (Peptides)
RN  - 0 (Proton Pumps)
RN  - 42HK56048U (Tyrosine)
RN  - EC 2.7.11.13 (Protein Kinase C)
RN  - EC 3.6.1.- (GTP-Binding Proteins)
RN  - EC 3.6.3.14 (Proton-Translocating ATPases)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Calcium/physiology
MH  - Chemotactic Factors/*physiology
MH  - GTP-Binding Proteins/physiology
MH  - Humans
MH  - Neutrophils/*enzymology
MH  - Peptides/physiology
MH  - Phosphorylation
MH  - Protein Kinase C/physiology
MH  - Proton Pumps/*physiology
MH  - Proton-Translocating ATPases/metabolism
MH  - Signal Transduction/physiology
MH  - Tyrosine/metabolism
MH  - Vacuoles/physiology
EDAT- 1995/12/01 00:00
MHDA- 1995/12/01 00:01
CRDT- 1995/12/01 00:00
PHST- 1995/12/01 00:00 [pubmed]
PHST- 1995/12/01 00:01 [medline]
PHST- 1995/12/01 00:00 [entrez]
AID - 10.1002/jcp.1041650317 [doi]
PST - ppublish
SO  - J Cell Physiol. 1995 Dec;165(3):588-99. doi: 10.1002/jcp.1041650317.