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Corticotrophin releasing factor (CRF) acts via two family B G-protein-coupled receptors, CRFR1 and CRFR2. Additional subtypes exist due to alternative splicing. CRFR1α is the most widely expressed subtype and lacks a 29-residue insert in the first intracellular loop that is present in CRFR1β. It has been shown previously that co-expression of CRFR1β with receptor activity modifying protein 2 (RAMP2) in HEK 293S cells increased the cell-surface expression of both proteins suggesting a physical interaction as seen with RAMPs and calcitonin receptor-like receptor (CLR). This study investigated the ability of CRFR1α, CRFR1β and CRFR2β to promote cell-surface expression of FLAG-tagged RAMP2. Four different cell-lines were utilised to investigate the effect of varying cellular context; COS-7, HEK 293T, HEK 293S and [ΔCTR]HEK 293 (which lacks endogenous calcitonin receptor). In all cell-lines, CRFR1α and CRFR1β enhanced RAMP2 cell-surface expression. The magnitude of the effect on RAMP2 was dependent on the cell-line ([ΔCTR]HEK 293 > COS-7 > HEK 293T > HEK 293S). RT-PCR indicated this variation may relate to differences in endogenous RAMP expression between cell types. Furthermore, pre-treatment with CRF resulted in a loss of cell-surface FLAG-RAMP2 when it was co-expressed with CRFR1 subtypes. CRFR2β co-expression had no effect on RAMP2 in any cell-line. Molecular modelling suggests that the potential contact interface between the extracellular domains of RAMP2 and CRF receptor subtypes is smaller than that of RAMP2 and CRL, the canonical receptor:RAMP pairing, assuming a physical interaction. Furthermore, a specific residue difference between CRFR1 subtypes (glutamate) and CRFR2β (histidine) in this interface region may impair CRFR2β:RAMP2 interaction by electrostatic repulsion.

During the northern winter monsoon, the Madden-Julian Oscillation (MJO) and northeasterly cold-surges are active over the eastern Indian Ocean and western Pacific. The MJO consists of an active (wet) phase and inactive (dry) phase and varies over global spatial and intraseasonal time scales. Interactions between the MJO and northeasterly cold-surges, which vary over regional space and synoptic time scales, are examined. The interactions are examined between 1979-1998 using winds at 1000 hPa and a representation of convection during the northern winter monsoon. To identify interactions, the active and inactive phases of the MJO are divided into early or late phases (based on MJO duration). Examination of composite maps based on cold-surges defined to occur during each phase of the MJO revealed that the phase of the MJO acts to either enhance or weaken a cold-surge that may have been forced by the mid-latitudes. When MJO convection is located over the South China Sea, the surge intensifies. The favorable convection pattern dominates the unfavorable pressure-wind pattern of the MJO. When the MJO dry-phase is over the South China Sea, mid-latitude forcing appears to interact favorably with the pressure-wind pattern of the MJO to dominate the unfavorable MJO convection pattern, http://archive.org/details/acompositestudyo109457650, U.S. Navy (U.S.N.) author.

Presented at the Symposium on the Impacts of an Ice-Diminishing Arctic on Naval & Maritime Operations (4th), June 20-22, 2011, Washington, DC.

During the northern winter monsoon, the Madden-Julian Oscillation (MJO) and northeasterly cold-surges are active over the eastern Indian Ocean and western Pacific. The MJO consists of an active (wet) phase and inactive (dry) phase and varies over global spatial and intraseasonal time scales. Interactions between the MJO and northeasterly cold-surges, which vary over regional space and synoptic time scales, are examined. The interactions are examined between 1979-1998 using winds at 1000 hPa and a representation of convection during the northern winter monsoon. To identify interactions, the active and inactive phases of the MJO are divided into early or late phases (based on MJO duration). Examination of composite maps based on cold-surges defined to occur during each phase of the MJO revealed that the phase of the MJO acts to either enhance or weaken a cold-surge that may have been forced by the mid-latitudes. When MJO convection is located over the South China Sea, the surge intensifies. The favorable convection pattern dominates the unfavorable pressure-wind pattern of the MJO. When the MJO dry-phase is over the South China Sea, mid-latitude forcing appears to interact favorably with the pressure-wind pattern of the MJO to dominate the unfavorable MJO convection pattern