Our recent studies demonstrated the localization of protein 4.1B, a member of the 4.1 skeletal membrane proteins, to the basolateral membranes of the S1-S2 renal proximal tubules. In the present ...studies, we investigated the presence of binding partners that could form a molecular complex with the 4.1B protein. Immunohistochemistry revealed the localization of p55, a membrane-associated guanylate kinase, and the sodium bicarbonate cotransporter1 (NBC1), to the basolateral membrane domain of S1-S2 in mouse renal proximal tubules. Using immunoprecipitation of kidney lysates with anti-p55 antibody, a positive band was blotted with anti-4.1B antibody. GST fusion proteins including the NBC1 and 4.1B regions were confirmed to bind with each other by electrophoresis after mixing. Both NBC1- and 4.1B-specific bands were detected in renal protein mixtures immunoprecipated by either anti-4.1B- or NBC1-specific antibodies. It is likely that NBC1, 4.1B, and p55 form a molecular complex in the basolateral membrane of the kidney S1-S2 proximal tubules. We propose that the 4.1B-containing membrane skeleton may play a role in regulating the Na+ and HCO3
- reabsorption in S1-S2 proximal tubules.
Using a high‐resolution climate model, we projected future sea level and its variability based on two scenarios for 21st century greenhouse gas emission. The globally averaged sea level rise ...attributable to the steric contribution was 23 and 30 cm for the two scenarios. The results of the high‐resolution model and a medium‐resolution version of the same model for global and local sea level change agreed well. However, the high‐resolution model represented more detailed ocean structure changes under global warming. The changes affected not only the spatial distribution of sea level rise, but also the changes in local sea level variability associated with ocean eddies. The enhanced eddy activity was responsible for extreme sea level events.
For the first time, using a high‐resolution atmosphere‐ocean coupled general circulation model (CGCM), we succeed in reproducing the far‐reaching effects of the Hawaiian Islands, recently showed by ...satellite observations. The model reproduces the distributions of sea surface temperature (SST), surface winds and cloud liquid water (CLW) in the wake of the Hawaiian Islands. It is revealed that these distributions are caused by the Hawaiian Lee Counter Current (HLCC) and that this current is driven by the wind‐curls induced by the orographic effect of the islands, as suggested from an observational study. It is also shown that wind changes around the Hawaiian Islands can further affect the speed of the North Equatorial Current (NEC) and SST over the current, and intra‐annual variability in CLW to the west of the islands is governed, not only by SST but also by wind speed.
Observed regional distribution of sea level changes for recent decades Regional sea level changes due to density changes in water masses Decomposition of baroclinic response of sea level change Using ...a gridded ocean temperature and salinity field based on observations, the regional distribution of sea level changes during the last few decades was investigated. We calculated the baroclinic sea level change and decomposed it into vertical modes of pressure perturbation for internal waves, considering the vertical structure of the baroclinic pressure change. The first mode is associated with vertical displacement of the main pycnocline, which is generally a dynamical response to wind forcing, as demonstrated by previous studies using shallow water models. Regional sea level variations associated with this mode have large magnitudes, especially in the tropics, where, as shown by previous studies, interannual variability is relatively large compared to sea level changes. Other factors affecting sea level include changes in water mass density and horizontal movement of water masses. These are characterized as second and higher modes, and their combined effect on the amplitude of regional sea level changes is comparable with that of the first mode, especially in subtropical gyre regions. In the North Pacific, the combined second and higher order modes give rise to significant positive sea level trends. These long-term sea level trends are induced by steric contributions resulting from warming and freshening of the subtropical mode waters. This result suggests that changes in water mass properties such as temperature and salinity are also important for replicating local sea level change, especially in the subtropical gyre region.
We formulate a new conceptual model, named “
MT
2”, to describe global ocean heat uptake, as simulated by atmosphere–ocean general circulation models (AOGCMs) forced by increasing atmospheric CO
2
, ...as a function of global-mean surface temperature change
T
and the strength of the Atlantic meridional overturning circulation (AMOC,
M
).
MT
2 has two routes whereby heat reaches the deep ocean. On the basis of circumstantial evidence, we hypothetically identify these routes as low- and high-latitude. In low latitudes, which dominate the global-mean energy balance, heat uptake is temperature-driven and described by the two-layer model, with global-mean
T
as the temperature change of the upper layer. In high latitudes, a proportion
p
(about 14%) of the forcing is taken up along isopycnals, mostly in the Southern Ocean, nearly like a passive tracer, and unrelated to
T
. Because the proportion
p
depends linearly on the AMOC strength in the unperturbed climate, we hypothesise that high-latitude heat uptake and the AMOC are both affected by some characteristic of the unperturbed global ocean state, possibly related to stratification.
MT
2 can explain several relationships among AOGCM projections, some found in this work, others previously reported:
∙
Ocean heat uptake efficiency correlates strongly with the AMOC.
∙
Global ocean heat uptake is not correlated with the AMOC.
∙
Transient climate response (TCR) is anticorrelated with the AMOC.
∙
T
projected for the late twenty-first century under high-forcing scenarios correlates more strongly with the effective climate sensitivity than with the TCR.
We cloned from a rat brain cDNA library a novel cDNA and named it a potential synaptic guanine nucleotide exchange factor (GEF) for Arf (synArfGEF (Po)) (GenBank Accession no. AB057643) based on its ...domain structure and localization. The cloned gene was 7410 bases long with a 3585‐bp coding sequence encoding a protein of 1194 amino acids. The deduced protein contained a coiled‐coil structure in the N‐terminal portion followed by Sec7 and Plekstrin homology (PH) domains. Thus, the protein was a member of the Sec7 family of proteins, GEFs. Conservation of the ADP‐ribosylation factor (Arf)‐binding sequence suggested that the protein was a GEF for Arf. The gene was expressed specifically in the brain, where it exhibited region‐specific expression. The protein was highly enriched in the postsynaptic density (PSD) fraction prepared from the rat forebrain. Uniquely, the protein interacted with PSD‐95, SAP97 and Homer/Vesl 1/PSD‐Zip45 via its C‐terminal PDZ‐binding motif and co‐localized with these proteins in cultured cortical neurons. These results supported its localization in the PSD. The postsynaptic localization was also supported by immunohistochemical examination of the rat brain. The mRNA for the synArfGEF was also localized to dendrites, as well as somas, of neuronal cells. Thus, both the mRNA and the protein were localized in the postsynaptic compartments. These results suggest a postsynaptic role of synArfGEF in the brain.
Using atmosphere‐ocean coupled general circulation models (CGCMs) with different resolution, we investigate the dependency on horizontal resolution to reproduce the seasonal variation of the Mindanao ...Dome (MD). The seasonal cycle of the MD is successfully simulated in the high resolution CGCM. It is generated by local Ekman upwelling and destroyed by westward warm anomaly propagation during late spring. The warm anomaly is caused by Ekman downwelling induced by westward wind stress and negative wind stress curl anomaly associated with southward shift of the inter‐tropical convergence zone in the central tropical Pacific. However, in the lower resolution model, the seasonal cycle is not represented owing to the insufficient wind forcing. The higher resolution atmospheric model improves the wind forcing in the CGCM, but it doesn't go far enough. The reproduction of the wind forcing depends not only horizontal resolution of an atmospheric model but also on that of an ocean model.
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