The mitochondria and endoplasmic reticulum (ER) are two fundamental organelles found within cells. The study of the interactions between them is a major field in cellular biology. The mitochondria and ER have areas that can interact with each other. In the present study, it was hypothesized that the motor protein myosin-19 (Myo19) on mitochondria interacts with the endoplasmic reticulum-associated protein inverted formin 2-CAAX (INF2-CAAX). To address this hypothesis, immunocytochemistry, confocal microscopy, colocalization analysis and the proximity ligation assay (PLA) were carried out. Pearson correlation coefficient (PCC) colocalization analysis of confocal images gave information on the distribution of organelles and proteins in space. The PLA provided more precise information on the regions of close association of the proteins of interest in human osteosarcoma (U2OS) cells. Ca2+ activation via ionomycin was also tested. It was demonstrated that Ca2+ stimulation significantly increases the interaction between mitochondria and ER as well as Myo19 and INF2-CAAX. Since Myo19 and INF2-CAAX reside at mitochondria and ER, respectively, these results suggest that Myo19 and INF2-CAAX might have an important role in the interaction of the mitochondria and ER. It is hypothesized that such an interaction may be involved in mitochondrial dynamics, such as fission.

Date of publication

Summer 6-29-2022

Document Type

Thesis (Local Only Access)



Persistent identifier


Committee members

Mitsuo Ikebe PhD, Hua Tang PhD, Osamu Sato PhD, Guoqing Qian PhD, Pierre Neuenschwander PhD


Master of Science in Biotechnology

Available for download on Wednesday, July 10, 2024