title: Comparison of gating dynamics of different IP3R channels with immune algorithm searching for channel parameter distributions.
abstract: The gating properties of the inositol 1, 4, 5-trisphosphate (IP3) receptor (IP3R) are determined by the binding and unbinding capability of Ca2+ions and IP3messengers. With the patch clamp experiments, the stationary properties have been discussed for Xenopus oocyte type-1 IP3R (Oo-IP3R1), type-3 IP3R (Oo-IP3R3) and Spodoptera frugiperda IP3R (Sf-IP3R). In this paper, in order to provide insights about the relation between the observed gating characteristics and the gating parameters in different IP3Rs, we apply the immune algorithm to fit the parameters of a modified DeYoung-Keizer model. By comparing the fitting parameter distributions of three IP3Rs, we suggest that the three types of IP3Rs have the similar open sensitivity in responding to IP3. The Oo-IP3R3 channel is easy to open in responding to low Ca2+concentration, while Sf-IP3R channel is easily inhibited in responding to high Ca2+concentration. We also show that the IP3binding rate is not a sensitive parameter for stationary gating dynamics for three IP3Rs, but the inhibitory Ca2+binding/unbinding rates are sensitive parameters for gating dynamics for both Oo-IP3R1 and Oo-IP3R3 channels. Such differences may be important in generating the spatially and temporally complex Ca2+oscillations in cells. Our study also demonstrates that the immune algorithm can be applied for model parameter searching in biological systems.
authors.affiliation: Department of Physics, Xiamen University, Xiamen 361000, People's Republic of China.
authors.forename: Xiuhong
authors.initials: X
authors.lastname: Cai
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Qi
authors.forename: Fang
authors.initials: F
authors.lastname: Wei
authors.forename: Jianyong
authors.initials: J
authors.lastname: Chen
authors.forename: Jianwei
authors.initials: J
authors.lastname: Shuai
mesh_terms: D000465:Algorithms; D029845:Amphibian Proteins / Q000737:chemistry*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000737:chemistry*; D019476:Insect Proteins / Q000737:chemistry*; D015640:Ion Channel Gating; D008954:Models, Biological; D051381:Rats / Q000378:metabolism; D018411:Spodoptera / Q000737:chemistry / Q000378:metabolism; D014981:Xenopus / Q000378:metabolism
chemical_list: D029845:Amphibian Proteins; D053496:Inositol 1,4,5-Trisphosphate Receptors; D019476:Insect Proteins; D002118:Calcium