| First Author | Rossi A | Year | 2012 |
| Journal | J Cell Sci | Volume | 125 |
| Issue | Pt 18 | Pages | 4405-12 |
| PubMed ID | 22718347 | Mgi Jnum | J:198879 |
| Mgi Id | MGI:5499692 | Doi | 10.1242/jcs.109603 |
| Citation | Rossi A, et al. (2012) Super-resolution imaging of aquaporin-4 orthogonal arrays of particles in cell membranes. J Cell Sci 125(Pt 18):4405-12 |
| abstractText | Aquaporin-4 (AQP4) is a water channel expressed in astrocytes, skeletal muscle and epithelial cells that forms supramolecular aggregates in plasma membranes called orthogonal arrays of particles (OAPs). AQP4 is expressed as a short isoform (M23) that forms large OAPs, and a long isoform (M1) that does not form OAPs by itself but can mingle with M23 to form relatively small OAPs. AQP4 OAPs were imaged with ~20 nm spatial precision by photoactivation localization microscopy (PALM) in cells expressing chimeras of M1- or M23-AQP4 with photoactivatable fluorescent proteins. Native AQP4 was imaged by direct stochastic optical reconstruction microscopy (dSTORM) using a primary anti-AQP4 antibody and fluorescent secondary antibodies. We found that OAP area increased from 1878+/-747 to 3647+/-958 nm(2) with decreasing M1:M23 ratio from 1:1 to 1:3, and became elongated. Two-color dSTORM indicated that M1 and M23 co-assemble in OAPs with a M1-enriched periphery surrounding a M23-enriched core. Native AQP4 in astrocytes formed OAPs with an area of 2142+/-829 nm(2), which increased to 5137+/-1119 nm(2) with 2-bromopalmitate. PALM of AQP4 OAPs in live cells showed slow diffusion (average ~10(-12) cm(2)/s) and reorganization. OAP area was not altered by anti-AQP4 IgG autoantibodies (NMO-IgG) that cause the neurological disease neuromyelitis optica. Super-resolution imaging allowed elucidation of novel nanoscale structural and dynamic features of OAPs. |
