Calcium- and zinc-binding proteins in intracellular transport.
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.
Aballay
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A
Instituto de Histología y Embriología (IHEM-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.
Arenas
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GN
Mayorga
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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*
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