Preliminary Study Of The Mechanism For The Intracellular Transportation Of PCDH15

In the auditory conduction process,the sound is converted to an electrical signal by electromechanical transduction processes,which occur in cingulate hair cells.After the mechanical signal is stimulated,the core element of the MET device-the tip-link tension increases,the MET channel is open,which leads to the generation of cell receptor potential.Protocadherin 15(PCDH15),which is instrumental in the progress of electromechanical transduction channel,is one of the components of hair cell tip-links.PCDH15 has three different splicing.They all have transmembrane regions that differ only in the intracellular segment and function redundantly during mechanical-electrical transduction during cesarean development.Mutation of the PCDH15 gene can lead to hearing loss.However,so far,the study of PCDH15 intracellular transport regulatory mechanisms are still not shown according to other literatures.In this paper,we had a preliminary study on a possible regulatory mechanism of PCDH15 transmembrane transport.The yeast two-hybrid screen was performed to explore the protein which interacts with PCDH15.We found that PIST(a protein associated with the Golgi,with a PDZ domain)was able to interact with PCDH15-CD3.And then we verified the interaction between PCDH15 with PIST using co-immunoprecipitation and Subcellular co-localization.We found that this interaction was connected by the PDZ domain-binding interface(PBI)at the C-terminus of PCDH15-CD3 and the PDZ domain of PIST.Through the interaction of both,PIST retained PCDH15-CD3 on the reverse Golgi network(TGN),thereby reducing the expression of PCDH15-CD3 on the cell membrane.Our previous work found that PIST was able to regulate the expression of cadherin 23(CDH23),which is another tip-link component.In a word,our findings suggest that we found that PIST was able to regulate intracellular transport and cell membrane localization of Tip-link-related cadherin PCDH15-CD3 and CDH23.It has been shown that PCDH15 can bind to the Usher protein Harmonin,PDZD7,Whirlin,containing PDZ domains.However,the mode of action between different PCDH15 subtypes and these proteins has not been reported.We investigated the effect of Whirlin and PDZD7 with PCDH15-CD3 by immunoprecipitation,but not with PCDH15-CD1 or PCDH15-CD2.In addition,immunoprecipitation experiments did not detect any combination of PCDH15 subtypes and Harmonin.Subcellular co-localization experiments also yielded similar results.