Combining airborne remote, in situ, and expendable probe sensors with air-deployed ocean platforms provides a strategy for expanding knowledge of illusive high-wind air-sea fluxes in difficult-to-predict storms.

The human Usher syndrome (USH) is the most frequent cause of combined deaf-blindness. USH is genetically heterogeneous with at least 12 chromosomal loci assigned to three clinical types, USH1-3. Although these USH types exhibit similar phenotypes in human, the corresponding gene products belong to very different protein classes and families. The scaffold protein harmonin (USH1C) was shown to integrate all identified USH1 and USH2 molecules into protein networks. Here, we analyzed a protein network organized in the absence of harmonin by the scaffold proteins SANS (USH1G) and whirlin (USH2D). Immunoelectron microscopic analyses disclosed the colocalization of all network components in the apical inner segment collar and the ciliary apparatus of mammalian photoreceptor cells. In this complex, whirlin and SANS directly interact. Furthermore, SANS provides a linkage to the microtubule transport machinery, whereas whirlin may anchor USH2A isoform b and VLGR1b (very large G-protein coupled receptor 1b) via binding to their cytodomains at specific membrane domains. The long ectodomains of both transmembrane proteins extend into the gap between the adjacent membranes of the connecting cilium and the apical inner segment. Analyses of Vlgr1/del7TM mice revealed the ectodomain of VLGR1b as a component of fibrous links present in this gap. Comparative analyses of mouse and Xenopus photoreceptors demonstrated that this USH protein network is also part of the periciliary ridge complex in Xenopus. Since this structural specialization in amphibian photoreceptor cells defines a specialized membrane domain for docking and fusion of transport vesicles, we suggest a prominent role of the USH proteins in cargo shipment.

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T he record-setting 2005 hurricane season has highlighted the urgent need for a better understanding of the factors that contribute to hurricane intensity, and for the development of corresponding advanced hurricane prediction models to improve intensity forecasts. The lack of skill in present forecasts of hurricane intensity may be attributed, in part, to deficiencies in the current prediction models-insufficient grid resolution, inadequate surface and boundary-layer formulations, and the lack of full coupling to a dynamic ocean. The extreme high winds, intense rainfall, large ocean waves, and copious sea spray in hurricanes push the surface-exchange parameters for temperature, water vapor, and momentum into untested regimes.The Coupled Boundary Layer Air-Sea Transfer (CBLAST)-Hurricane program is aimed at developing improved parameterizations using observations from the CBLAST-Hurricane field program (described by Peter Black and colleagues elsewhere in this issue) that will be suitable for the next generation of hurricane-prediction models. The most innovative aspect of the CBLAST-Hurricane modeling effort is the development and testing of a fully coupled 1 atmo- AIR-SEA INTERACTION AND HURRI- CANES.Hurricanes rarely reach their maximum potential intensity (MPI, as defined by Kerry Emanuel and Greg Holland). Many factors can prevent a given storm from reaching MPI, including environmental vertical wind shear, distribution of troposphere water vapor, hurricane internal dynamics, and air-sea interactions. The effect of air-sea interactions on hurricane structure and intensity change is the main focus of the CBLAST-Hurricane program. Intensification of a hurricane depends upon two competing processes at the air-sea interface-the heat and moisture fluxes that fuel the storm and the dissipation of kinetic energy associated with wind stress on the ocean surface. Air-sea interaction is especially important within the extremely high winds (up to 75 m s -1 ) and strong gradient zones of temperature and pressure located in the inner core (eye and eyewall) of a hurricane. The enthalpy and momentum exchange coefficients under the extreme high-wind conditions are, of course, very difficult to determine in precisely the regions where they are most important. The stress is supported mainly by waves in the wavelength range of 0.1-10 m, which are an unresolved "spectral tail" in present wave models. In the November 1995 Journal of the Atmospheric Sciences, Emanuel proposed that storm intensity is largely controlled by the ratio of the air-sea enthalpy MARCH 2007 BAPIS^ | 15 els-are noted in a schematic in Fig. 1. A specific issue we emphasize here is the determination and parameterization of the air-sea momentum and enthalpy fluxes in conditions of extremely high and timevarying hurricane winds. FIG. I.Schematics of a coupled atmosphere-wave-ocean modeling system with the component atmosphere, surface wave, and ocean circulation models, as well as the coupling parameter exchanges between each of the component models.and mome...

␤cyto-Actin and ␥cyto-actin are ubiquitous proteins thought to be essential building blocks of the cytoskeleton in all non-muscle cells. Despite this widely held supposition, we show that ␥cyto-actin null mice (Actg1 ؊/؊ ) are viable. However, they suffer increased mortality and show progressive hearing loss during adulthood despite compensatory up-regulation of ␤cyto-actin. The surprising viability and normal hearing of young Actg1 ؊/؊ mice means that ␤cyto-actin can likely build all essential non-muscle actin-based cytoskeletal structures including mechanosensory stereocilia of hair cells that are necessary for hearing. Although ␥cyto-actin-deficient stereocilia form normally, we found that they cannot maintain the integrity of the stereocilia actin core. In the wild-type, ␥cyto-actin localizes along the length of stereocilia but re-distributes to sites of F-actin core disruptions resulting from animal exposure to damaging noise. In Actg1 ؊/؊ stereocilia similar disruptions are observed even without noise exposure. We conclude that ␥cyto-actin is required for reinforcement and long-term stability of F-actin-based structures but is not an essential building block of the developing cytoskeleton.actin ͉ cytoskeleton ͉ hearing T here are six genes encoding six vertebrate actins that are classified according to where they are predominately expressed. ␣ skeletal -Actin, ␣ smooth -actin, ␣ cardiac -actin, and ␥ smoothactin are primarily found in muscle cells, whereas cytoplasmic ␤ cyto -actin and ␥ cyto -actin are ubiquitously and highly expressed in non-muscle cells, as reviewed elsewhere (1). Athough ␤ cytoactin and ␥ cyto -actin differ at only four biochemically similar amino acid residues in their N-termini, several lines of evidence suggest that each protein is functionally distinct. The amino acid sequences of ␤ cyto -and ␥ cyto -actin are each exactly conserved among avian and mammalian species. In addition, ␤ cyto -and ␥ cyto -actin proteins are differentially localized (2-5) and posttranslationally modified (6). Finally, although dominant missense mutations in ACTB encoding ␤ cyto -actin are associated with syndromic phenotypes including severe developmental malformations and bilateral deafness (7), humans carrying a variety of dominant missense mutations in ACTG1 develop postlingual nonsyndromic progressive hearing loss (DFNA20, OMIM 604717) (8-11).␥ cyto -Actin is widely expressed in the inner ear sensory epithelial cells on which mammalian hearing depends. These cells are organized in rows along the cochlea length: one row of inner hair cells (IHCs) and three rows of outer hair cells (OHCs) (Fig. 2A). IHCs function as auditory receptors, converting sound energy into neuronal signals, whereas OHCs enhance sensitivity to sound stimuli, as reviewed elsewhere (12). The apical surface of a hair cell is topped with actin-rich microvilli-derived protrusions termed stereocilia, which deflect in response to sound stimuli, initiating mechanoelectrical transduction (Fig. 2B). ␤ cyto -and ␥ cyto -Actin are both thou...