title: Calcium- and zinc-binding proteins in intracellular transport.
abstract: The complex mechanism of intracellular transport is regulated by free calcium in different manners. Calcium binding proteins regulate several aspects of the vesicle fusion mechanism mediated by NSF (N-ethylmaleimide sensitive fusion factor). At least in some regulated exocytosis, calcium-binding proteins are the trigger for fusion downstream of NSF, Still, calcium-binding proteins, such as annexins, may be part of a different fusion mechanism mediating some specific transport steps or working in parallel to the NSF-dependent fusion process. Calcium is not the only ion necessary for the function of factors involved in vesicular transport. A zinc requirement has been also proposed. One of the zinc-dependent factors is probably a protein with a cysteine-rich region that coordinates zinc and binds phorbol esters. Although protein kinase C is the more prominent family of proteins carrying this domain, the factor necessary for transport does not appear to function as a kinase.
authors.affiliation: Instituto de Histología y Embriología (IHEM-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.
authors.forename: A
authors.initials: A
authors.lastname: Aballay
authors.forename: G N
authors.initials: GN
authors.lastname: Arenas
authors.forename: L S
authors.initials: LS
authors.lastname: Mayorga
mesh_terms: D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000502:physiology*; D002352:Carrier Proteins / Q000502:physiology; D002460:Cell Line; D018699:Coated Vesicles / Q000502:physiology; D004285:Dogs; D005089:Exocytosis / Q000502:physiology; D007424:Intracellular Fluid / Q000378:metabolism; D007668:Kidney; D008561:Membrane Fusion; D008667:Metalloproteins / Q000502:physiology*; D052066:N-Ethylmaleimide-Sensitive Proteins; D010703:Phorbol Esters / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000502:physiology; D033921:Vesicular Transport Proteins; D015032:Zinc / Q000502:physiology*
chemical_list: D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D008667:Metalloproteins; D010703:Phorbol Esters; D033921:Vesicular Transport Proteins; D011493:Protein Kinase C; D052066:N-Ethylmaleimide-Sensitive Proteins; D015032:Zinc; D002118:Calcium