Secretory glands including salivary glands by many hormonal inputs produce and secrete biological fluids determined by variety of ion transporters. Spinophilin is a multifunctional scaffolding protein, which involved in receptor signaling and regulation of anion exchangers AE2 activity. We found that spinophilin expressed in salivary glands. The role of salivary spinophilin on the modulation of chloride/bicarbonate exchange remains unknown. The spinophilin enhanced AE2 activity and associated with a STE20/SPS1-related kinase and showed an additive effect on the modulation of the activity of AE2. The cholinergic stimulation and subsequent intracellular Ca2+ increase was required for the interaction with AE2 and spinophilin and abrogated the enhanced effect of spinophilin on Cl- transporting activity. Ductal chloride/bicarbonate exchange activity was increased in pretreatment with carbachol. The CaMKII inhibitor KN-93 suppressed the chloride/bicarbonate exchange activity of ducts, suggesting that CaMKII was required for ductal chloride/bicarbonate exchange activity. Additionally, microtubule destabilization by nocodazole attenuated the interaction of AE2 and spinophilin and almost abolished the ductal chloride/bicarbonate exchange activity. The treatment of siRNA-spinophilin on the isolated salivary ducts also reduced the ductal chloride/bicarbonate exchange activity. Therefore, role of salivary spinophilin on AE2 may facilitate the Cl- influx from basolateral in salivary glands in response to cholinergic inputs.
Bibliographical noteFunding Information:
The DNA constructs were kindly provided by Dr. Shmuel Muallem in National Institutes of Health/National Institute of Dental and Craniofacial Research, Bethesda, MD, United States. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government [NRF-2017R1D1A1B03029570 (JH), NRF-2016 R1A5A2008630 (DS), and NRF-2015R1A2A1A15054157 (DS)].
© 2018 Lee, Lee, Shin and Hong.
All Science Journal Classification (ASJC) codes
- Physiology (medical)