Abstract
The plasma membrane Ca2+-ATPase-2 (PMCA2) is expressed in stereocilia of hair cells of the inner ear, whereas PMCA1 is expressed in the basolateral plasma membrane of hair cells. Both extrude excess Ca2+ from the cytosol. They are predicted to contain ten membrane-spanning segments, two large cytoplasmic loops as well as cytosolic N- and C-termini. Several isoform variants are generated for both PMCA1 and PMCA2 by alternative splicing, affecting their first cytosolic loop (A-site) and their C-terminal tail. To understand how these isoforms are differentially targeted in hair cells, we investigated their targeting regions and expression in hair cells. Our results show that a Leu-Ile motif in 'b'-tail splice variants promotes PMCA1b and PMCA2b basolateral sorting in hair cells. Moreover, apical targeting of PMCA2 depends on the size of the A-site-spliced insert, suggesting that the conformation of the cytoplasmic loop plays a role in apical targeting.
Original language | English (US) |
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Pages (from-to) | 2995-3007 |
Number of pages | 13 |
Journal | Journal of cell science |
Volume | 119 |
Issue number | 14 |
DOIs | |
State | Published - Jul 15 2006 |
Keywords
- Alternative splicing
- Inner ear explant
- Intracellular loop
- Leucine-isoleucine signal
- Stereocilia
ASJC Scopus subject areas
- Cell Biology