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Roles of the Na,K‐ATPase α4 isoform and the Na + /H + exchanger in sperm motility
Author(s) -
Woo Alison L.,
James Paul F.,
Lingrel Jerry B.
Publication year - 2002
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.90002
Subject(s) - ouabain , nigericin , motility , ionophore , biology , valinomycin , sperm , sperm motility , gene isoform , intracellular , atpase , intracellular ph , monensin , ion transporter , biochemistry , microbiology and biotechnology , biophysics , sodium , enzyme , membrane potential , chemistry , membrane , organic chemistry , gene , botany
The Na,K‐ATPase generates electrochemical gradients that are used to drive the coupled transport of many ions and nutrients across the plasma membrane. The functional enzyme is comprised of an α and β subunit and families of isoforms for both subunits exist. Recent studies in this laboratory have identified a biological role for the Na,K‐ATPase α4 isoform in sperm motility. Here we further investigate the role of the Na,K‐ATPase carrying the α4 isoform, showing again that ouabain eliminates sperm motility, and in addition, that nigericin, a H + /K + ionophore, and monensin, a H + /Na + ionophore, reinitiate motility. These data, along with the observation that the K + ionophore valinomycin has no effect on the motility of ouabain‐inhibited sperm, suggest that ouabain may change intracellular H + levels in a manner that is incompatible with sperm motility. We have also localized NHE1 and NHE5, known regulators of intracellular H + content, to the same region of the sperm as the Na,K‐ATPase α4 isoform. These data highlight the important role of the Na,K‐ATPase α4 isoform in regulating intracellular H + levels, and provide evidence suggesting the involvement of the Na + /H + exchanger, which is critical for maintaining normal sperm motility. Mol. Reprod. Dev. 62: 348–356, 2002. © 2002 Wiley‐Liss, Inc.