Membrane dynamics during osteoclast differentiation

摘要

Vacuolar H{sup}+-ATPase (V-ATPase) is a multi-subunit enzyme with a membrane peripheral catalytic V1 and an intrinsic Vo sector. We found multiple isoforms of mouse Vo subunit a (a1, a2, a3 and a4), whereas c and c" subunits are encoded by single genes. The a1 isoforms exhibit 48～52% identity with each other and high similarity to subunit a of other species. The a1 isoform was mainly expressed in brain and liver. The a2 isoform was observed in heart and kidney in addition to brain and liver. Transcripts for the a3 isoform were strongly expressed in heart and liver. The a3 isoform was induced during osteoclast differentiation, and localized in the plasma membrane and cytoplasmic filamentous structures. We discuss functional divergence of these isoforms.