In developing xylem cells, microtubule bundles maintain the cellulose synthase complexes beneath the sites of secondary wall synthesis, while actin is required for delivery and rapid trafficking of complex-containing organelles around the cell [ 88].
FKBP51 binding favors cytoplasmic localization of the receptor complex, whereas the binding of FKBP52 enables nuclear trafficking of the complex through its association with dynein (Galigniana et al., 2001, 2010).
These organelles are deemed essential for trafficking of virulence complex proteins.
While it regulates maturation and trafficking of the complex, on the cell surface, short protein fragments present in blood or lymph could utilize this mechanism to alter the ligand composition on antigen presenting cells in a catalytic way.
Together, our results demonstrate that normal formation and trafficking of this complex are required for proper function of the common secretory pathway and subsequent development of hair bundles.
Moreover, these mutations could result in the interaction of the mutated DLG3 with NEDD4 -2) while also disrupting the trafficking of the complex toward the synapse,, (Fig. 1).
Defects in any one of the three USH proteins disrupt formation and trafficking of the complex and result in diminished levels of the other proteins, generalized trafficking defects and ER stress that triggers apoptosis.
This result is consistent with the trafficking defects seen by proximity labeling with Sec23 or Sec13 (Fig. 5), and further demonstrates that defects in assembly or trafficking of the complex produce a global reduction of the ERGIC.
The combination of coimmunoprecipitation and BRET studies reported here, together with information already published on the MRAP/MC2R interaction, enable us to construct a model for formation and trafficking of this complex.
Given the importance of close association of Cdh23, Harmonin and Myo7aa for assembly and intracellular trafficking of this complex of USH1 proteins and the requirement of Myo7a for the subcellular localization of Gpr98, whirlin and usherin in mouse mechanoreceptors (Michalski et al., 2007), we also examined the cell body localization of the USH2 proteins Ush2a, Gpr98 and Whirlinb.
