Abstract:

Objective To investigate the role that HSC 170 plays in the process of CgBtranslocation in chromaffin cells.Methods Pull-down, co-immunoprecipitation and mass spectrometry of proteins were used to identify the proteins interested.Results The present data show an interaction of CgBwith heat shock cognate protein 70(Hsc70) in the chromaffin cell.Abinding sequence of Hsc70 is determined in the C-terminal region of porcine CgB(Ser586-Arg602, SR-17).Moreover, phosphorylation of Ser595 in pCgBenhances its association with Hsc70.On the other hand, Hsc70 is eluted from ATP-Sepharose by incubation with phosphorylated SR-17 at Ser595.Western blot analyses show that both CgBand Hsc70 are present in the nucleus and cytoplasm of these cells.Conclusion The present results suggest that Hsc70 may participate in the process of CgBtranslocation in chromaffin cells and that phosphorylation of CgBis likely to mediate this process.

Key words: chromogranin B, heat shock cognate protein 70, phosphorylation, nuclear translocation