NaBC1 is a ubiquitous electrogenic Na+ -coupled borate transporter essential for cellular boron homeostasis and cell growth and proliferation.
Boron is a vital micronutrient in plants and may be essential for animal growth and development. Whereas the role of boron in the life cycle of plants is well documented, nothing is known about boron homeostasis and function in animal cells. NaBC1, the mammalian homolog of AtBor1, is a borate transporter. In the absence of borate, NaBC1 conducts Na(+) and OH(-) (H(+)), while in the presence of borate, NaBC1 functions as an electrogenic, voltage-regulated, Na(+)-coupled B(OH)(4)(-) transporter. At low concentrations, borate activated the MAPK pathway to stimulate cell growth and proliferation, and at high concentrations, it was toxic. Accordingly, overexpression of NaBC1 shifted both effects of borate to the left, whereas knockdown of NaBC1 halted cell growth and proliferation. These findings may reveal a previously unrecognized role for NaBC1 in borate homeostasis and open the way to better understanding of the many presumed physiological roles of borate in animals.
Park
Meeyoung
M
Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA.
Li
Qin
Q
Shcheynikov
Nikolay
N
Zeng
Weizong
W
Muallem
Shmuel
S
D000818:Animals; D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism*; D017920:Antiporters / Q000378:metabolism*; D001692:Biological Transport; D001881:Borates / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D004594:Electrophysiology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006706:Homeostasis; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D034622:RNA Interference; D011817:Rabbits; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D014982:Xenopus laevis / Q000235:genetics / Q000378:metabolism
D027321:Anion Transport Proteins; D017920:Antiporters; D001881:Borates; C425809:SLC4A11 protein, human; D049452:Green Fluorescent Proteins; D012964:Sodium