MOLECULAR MECHANISMS OF ION TRANSPORT BY THE SMG

描述（改编自研究者摘要）： 这个建议是为了了解流体的分子机制， 下颌下腺（SMG）的电解质分泌，病灶 分泌物的导管成分。 矢量离子输运 唾液腺上皮细胞需要特定离子的极化表达 运输机 此外，离子转运的调节和定位 管道系统的特性描述得很差。 一个全面的细胞 生理学、生物化学和分子生物学方法已经被提出来测试 该模型，这是本提案的工作假设。 的目的 建议：（1）研究新发现的CFTR的作用， ENaC对腺泡腔膜HCO_3 ~-、Cl ~-和Na ~+流出的影响 细胞。(2)为了检查与管腔平行的“推拉”模型， Cl-/HCO 3交换介导的Cl-转运;（3）确定 HCO 3流入基底外侧膜（BLM）的主要机制， LM中的K+-HCO 3流出;（4）评估是否直接相互作用 ENaC和CFTR调节这两个通道的活性，从而调节NaCl 吸收和耦合KHCO 3分泌;和（5）跟踪活动 在整体模型的背景下，单独的传输/路径。 这项研究将使用该小组以前用于研究离子的方法 胰腺细胞中的转运蛋白以及最近建立的技术 研究颌下腺导管中的离子转运蛋白。 通过使用 电生理学研究（膜片钳测量），荧光 测量（使用特定染料来确定细胞溶质pH和细胞内pH）。 各种离子的浓度），细胞体积测量，以及 免疫细胞化学，特异性离子的功能定位 已经提出了SMG导管细胞中的转运蛋白。

DESCRIPTION (Adapted from the investigator's Abstract): The overall goal of this proposal is to understand the molecular mechanism underlying fluid and electrolyte secretion by the submandibular salivary gland (SMG) with a focus on the ductal component of the secretion. Vectorial ion transport in salivary epithelial cells requires polarized expression of specific ion transporters. Further, the regulation and localization of the ion transport systems of the duct have been poorly characterized. A comprehensive cell physiological, biochemical, and molecular approach has been proposed to test the model, which is the working hypothesis of this proposal. The aims of the proposal are to: (1) study the role of the newly discovered CFTR and ENaC on HCO3-, Cl- and Na+ efflux in the luminal membrane (LM) of acinar cells.; (2) to examine the "pull-push" model in parallel with a luminal Cl-/HCO3 exchange in mediating transductal Cl-transport; (3) to determine the major mechanism of HCO3 influx in the basolateral membrane (BLM) and K+-HCO3 efflux in the LM; (4) to evaluate whether direct interaction between ENaC and CFTR regulates the activity of the two channels and thereby NaCl absorption and the coupled KHCO3 secretion; and (5) to follow the activity of the individual transport/pathways in the context of the overall model. The study will use methodology previously applied by this group to study ion transporters in pancreatic cells and also more recent techniques established to study the ion transporters in the submandibular gland duct. By using electrophysiological studies (patch clamp measurements), fluorescence measurement (using specific dyes to determine cytosolic pH and the concentrations of various ions), cell volume measurements, and immunocytochemistry, the functional localization of the specific ion transporters in the SMG ductal cell has been proposed.