Lysosome dynamics in neurons, maintaining cellular homeostasis

Abstract

Lysosomes are membrane-enclosed organelles found in nearly all eukaryotic cells. They are characterised by a highly acidic lumen which contains hydrolases. They are mainly responsible for the degradation of macromolecules and for providing cellular building blocks in times of stress using the autophagy or endolysosomal pathways. However, the function of lysosomes extends beyond its function in degradation, several novel functions have recently been ascribed to lysosomes. A lot of research in lysosome dynamics has been done in non-polarized cells. The dynamics of lysosomes is less established in polarized cells, such as neurons. Neurons are highly compartmentalized and pose spatially extended neuronal cytoplasm. The dependence of neurons on optimal lysosomal function is especially important since lysosome disfunction is linked to several neurodegenerative diseases. In this review, we describe the roles played by lysosomes in neurons and how they maintain cellular homeostasis. We will focus on transport and regulation of lysosomes and how this is special for highly polarized cells. Furthermore, we discuss non-degradative functions of lysosomes in neurons. And finally, how lysosome disfunction contributes to neurodegenerative diseases.