The Golgi body, Endoplasmic Reticulum and Lysosome together constitute the GERL system. It is mainly involved in the processes of exocytosis. Proteins are synthesized and secreted from the endoplasmic reticulum, packaged inside the Golgi apparatus into secretory vesicles and are secreted outside the cell by exocytosis. Lysosomes are also formed by this system.

Microtubules can be characterized as the numerous, hollow, ultrafine, non-membranous cylindrical structures present within the cytoplasm of a eukaryotic cell. They are composed of the globular proteins α-tubulin and β-tubulin. Microtubules play essential roles during cell division, movement of cilia and flagella, circulation and transport, morphogenesis and maintenance of the cytoskeleton.