Endoplasmic reticulum stress enhances the rate of endocytosis in calreticulin deficient cells

Publication date: Available online 5 December 2018Source: Biochimica et Biophysica Acta (BBA) - Molecular Cell ResearchAuthor(s): Hamid Massaeli, Divya Viswanathan, Dhanya Govind Pillai, Nasrin MesaeliAbstractCalreticulin an endoplasmic reticulum (ER) chaperone that is involved in the quality control process and plays an important role as a regulator of intracellular calcium homeostasis. Previously, we illustrated that loss of calreticulin function (crt−/−) results in the activation of ubiquitin-proteasome pathway facilitating the increased resistance to apoptosis. Our preliminary data illustrated a significant increase in the rate of endocytosis in crt−/− cells. Therefore, we hypothesized that loss of calreticulin function induces onset of ER stress that increases rate of endocytosis. To test this hypothesis, we measured endocytosis in the wild type (wt) and crt−/− cells using uptake of fluorescent dextran and showed a significant increase in the rate of its uptake in crt−/− cells as compared to wt cells.To determine endocytic pathway involved we examined both clathrin and caveolin-1 dependent endocytosis. Our results illustrated no change in the expression of clathrin heavy chain while there was a significant increase in the expression of caveolin-1 in the crt−/− cells as compared to the wt cells. Furthermore, using shRNA we illustrated that knockdown of clathrin heavy chain had no effect on rate of endocytosis in the crt−/− cells. While knock-down o...
Source: Biochimica et Biophysica Acta (BBA) Molecular Cell Research - Category: Molecular Biology Source Type: research