Structural determinants and specificities for ROMK1-phosphoinositide interaction Export

@article{citeulike:220924, abstract = {We have recently reported that direct interaction between phosphatidylinositol bisphosphate (PIP(2)) and the COOH-terminal cytoplasmic domain of ROMK1 is important for opening of the channel. We identified arginine-188 of ROMK1 as a critical residue for this interaction. Here, we further report that substitution of a neutral amino acid for lysine-181, arginine-217, or lysine-218 decreases single-channel open probability for the full-conductance state and increases the frequency of opening at a subconductance state. Compared with wild-type ROMK1 channels, these substitution mutants also display an increased sensitivity to the block by anti-PIP(2) antibodies and to inhibition by intracellular protons. These results indicate that, like arginine-188, lysine-181, arginine-217, and lysine-218 are also involved in interactions with PIP(2) and are critical for ROMK1 to open at full conductance. Using synthetic phosphoinositides containing phosphates at different positions in the head group, we also examined the specificities of phosphoinositides in the regulation of ROMK1 channels. We found that phosphoinositides containing phosphate at both positions 4 and 5 of the inositol head group have the highest efficacy in activating ROMK1 channels. These results suggest that phosphatidylinositol 4,5-bisphosphate is likely the important phosphoinositide in the regulation of ROMK1 channels in a physiological membrane milieu.}, author = {Zeng, W. Z. and Liou, H. H. and Krishna, U. M. and Falck, J. R. and Huang, C. L.}, citeulike-article-id = {220924}, journal = {American Journal of Physiology. Renal Physiology}, keywords = {ala, antibody, arginine, conductivity, glutamine, immunology, laevis, lysine, molecular, mutagenesis, oocytes, patch-clamp, phosphatidylinositol, pip2, potassium, relationship, sequence, site-directed, sites, structure-activity, techniques, transfection}, number = {5}, pages = {F826--34}, posted-at = {2005-06-06 17:48:07}, priority = {2}, title = {Structural determinants and specificities for ROMK1-phosphoinositide interaction}, volume = {282}, year = {2002} }

TY - JOUR ID - citeulike:220924 L3 - citeulike-article-id:220924 N2 - We have recently reported that direct interaction between phosphatidylinositol bisphosphate (PIP(2)) and the COOH-terminal cytoplasmic domain of ROMK1 is important for opening of the channel. We identified arginine-188 of ROMK1 as a critical residue for this interaction. Here, we further report that substitution of a neutral amino acid for lysine-181, arginine-217, or lysine-218 decreases single-channel open probability for the full-conductance state and increases the frequency of opening at a subconductance state. Compared with wild-type ROMK1 channels, these substitution mutants also display an increased sensitivity to the block by anti-PIP(2) antibodies and to inhibition by intracellular protons. These results indicate that, like arginine-188, lysine-181, arginine-217, and lysine-218 are also involved in interactions with PIP(2) and are critical for ROMK1 to open at full conductance. Using synthetic phosphoinositides containing phosphates at different positions in the head group, we also examined the specificities of phosphoinositides in the regulation of ROMK1 channels. We found that phosphoinositides containing phosphate at both positions 4 and 5 of the inositol head group have the highest efficacy in activating ROMK1 channels. These results suggest that phosphatidylinositol 4,5-bisphosphate is likely the important phosphoinositide in the regulation of ROMK1 channels in a physiological membrane milieu. IS - 5 JF - American Journal of Physiology. Renal Physiology EP - 34 TI - Structural determinants and specificities for ROMK1-phosphoinositide interaction VL - 282 SP - F826 KW - ala KW - antibody KW - arginine KW - conductivity KW - glutamine KW - immunology KW - laevis KW - lysine KW - molecular KW - mutagenesis KW - oocytes KW - patch-clamp KW - phosphatidylinositol KW - pip2 KW - potassium KW - relationship KW - sequence KW - site-directed KW - sites KW - structure-activity KW - techniques KW - transfection AU - Zeng, WZ AU - Liou, HH AU - Krishna, UM AU - Falck, JR AU - Huang, CL PY - 2002/// ER -