PT - JOURNAL ARTICLE AU - Vincent, Bruno AU - Beaudet, Alain AU - Dauch, Pascale AU - Vincent, Jean-Pierre AU - Checler, Frédéric TI - Distinct Properties of Neuronal and Astrocytic Endopeptidase 3.4.24.16: A Study on Differentiation, Subcellular Distribution, and Secretion Processes AID - 10.1523/JNEUROSCI.16-16-05049.1996 DP - 1996 Aug 15 TA - The Journal of Neuroscience PG - 5049--5059 VI - 16 IP - 16 4099 - http://www.jneurosci.org/content/16/16/5049.short 4100 - http://www.jneurosci.org/content/16/16/5049.full SO - J. Neurosci.1996 Aug 15; 16 AB - Endopeptidase 3.4.24.16 belongs to the zinc-containing metalloprotease family and likely participates in the physiological inactivation of neurotensin.The peptidase displays distinct features in pure primary cultured neurons and astrocytes. Neuronal maturation leads to a decrease in the proportion of endopeptidase 3.4.24.16-bearing neurons and to a concomitant increase in endopeptidase 3.4.24.16 activity and mRNA content. By contrast, there is no change with time in endopeptidase 3.4.24.16 activity or content in astrocytes. Primary cultured neurons exhibit both soluble and membrane-associated endopeptidase 3.4.24.16 activity. The latter behaves as an ectopeptidase on intact plated neurons and resists treatments with 0.2% digitonin and Na2CO3. Further evidence for an association of the enzyme with plasma membranes was provided by cryoprotection experiments and electron microscopic analysis. The membrane-associated form of endopeptidase 3.4.24.16 increased during neuronal differentiation and appears to be mainly responsible for the overall augmentation of endopeptidase 3.4.24.16 activity observed during neuronal maturation. Unlike neurons, astrocytes only contain soluble endopeptidase 3.4.24.16. Astrocytes secrete the enzyme through monensin, brefeldin A, and forskolin-independent mechanisms. This indicates that endopeptidase 3.4.24.16 is not released by classical regulated or constitutive secreting processes. However, secretion is blocked at 4°C and by 8 bromo cAMP and is enhanced at 42°C, two properties reminiscent of that of other secreted proteins lacking a classical signal peptide. By contrast, neurons appear unable to secrete endopeptidase 3.4.24.16.