The Na+/H+ exchanger NHE1 is required for directional migration stimulated via PDGFR-alpha in the primary cilium.
We previously demonstrated that the primary cilium coordinates platelet-derived growth factor (PDGF) receptor (PDGFR) alpha-mediated migration in growth-arrested fibroblasts. In this study, we investigate the functional relationship between ciliary PDGFR-alpha and the Na(+)/H(+) exchanger NHE1 in directional cell migration. NHE1 messenger RNA and protein levels are up-regulated in NIH3T3 cells and mouse embryonic fibroblasts (MEFs) during growth arrest, which is concomitant with cilium formation. NHE1 up-regulation is unaffected in Tg737(orpk) MEFs, which have no or very short primary cilia. In growth-arrested NIH3T3 cells, NHE1 is activated by the specific PDGFR-alpha ligand PDGF-AA. In wound-healing assays on growth-arrested NIH3T3 cells and wild-type MEFs, NHE1 inhibition by 5'-(N-ethyl-N-isopropyl) amiloride potently reduces PDGF-AA-mediated directional migration. These effects are strongly attenuated in interphase NIH3T3 cells, which are devoid of primary cilia, and in Tg737(orpk) MEFs. PDGF-AA failed to stimulate migration in NHE1-null fibroblasts. In conclusion, stimulation of directional migration in response to ciliary PDGFR-alpha signals is specifically dependent on NHE1 activity, indicating that NHE1 activation is a critical event in the physiological response to PDGFR-alpha stimulation.
Department of Biology, University of Copenhagen, Copenhagen O, Denmark.
Linda
L
Schneider
Christian-Martin
CM
Stock
Peter
P
Dieterich
Bo Hammer
BH
Jensen
Lotte Bang
LB
Pedersen
Peter
P
Satir
Albrecht
A
Schwab
Søren Tvorup
ST
Christensen
Stine Falsig
SF
Pedersen
D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D027682:Cation Transport Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D002460:Cell Line; D002465:Cell Movement / Q000235:genetics / Q000502:physiology*; D002923:Cilia / Q000378:metabolism* / Q000502:physiology; D007399:Interphase; D051379:Mice; D041681:NIH 3T3 Cells; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D015854:Up-Regulation
D027682:Cation Transport Proteins; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; C490997:Slc9a1 protein, mouse; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers; C075278:platelet-derived growth factor A; D000584:Amiloride; D020796:Receptor, Platelet-Derived Growth Factor alpha; C039614:ethylisopropylamiloride