The Role of Calcium in Intracellular Trafficking

M.      Micaroni

Abstract

The molecular mechanism of membrane fusion essential to vital cellular activities such as intracellular transport, hormone secretion, enzyme release, or neurotransmission, involve the assembly and disassembly of a specialized set of proteins in opposing bilayers. Recent evidences shed new light on the role Ca2+ has in the regulation of this mechanism in which the Golgi apparatus works as a central station; from here, Ca2+ ions are released into and recovered from the cytosol during the different steps of the cargo progression. In fact, transient cytosolic Ca2+ fluctuations take a crucial role to recruit proteins and enzymes Ca2+-sensitive on Golgi membranes where they are involved in membranes remodelling which is fundamental process for the fusion events that allow protein trafficking. Here I provide an overview of the role Ca2+ plays in intra-Golgi trafficking underlying some interesting aspects to clarify the mechanisms of cargo progression.

Keywords: ATPase calcium pump, calcium, Golgi apparatus, intra-Golgi trafficking, membrane fusion, secretory pathway, SERCA, SPCA, endocytic pathways, Chelation, exocytosis, thapsigargin, yeast, Caenorhabditis elegans, chloroquine, cytotoxicity, synaptic exocytosis, voltage-gated Ca2+ channels, Transient gradients, homeostasis, glycosylation