Characterization of metalloproteinase-like activities in barnacle (Balanus amphitrite) nauplii

The presence of extracellular matrix (ECM) degrading enzymes was investigated in naupliar stages of the barnacle Balanus aniphitrite Darwin. The results of substrate gel-zymography and quantitative assays demonstrated that naupliar extracts contain several protease activities that are specific towards gelatin substrates; some caseinolytic activity was also detected. Substrate specificity was observed in all naupliar stages (II-VI). The gelatinolytic activities showed dependence on both Ca2+ and Zn2+ and inhibition by EDTA, EGTA, and 1,10-phenanthroline. Also Mg2+ partially activated the enzymes, whereas Cd2+, Cu2+, Hg2+ and Pb2+ were inhibitory. The thermal denaturation profile was significantly different in the presence and absence of Ca2+ and Zn2+. Overall, the results indicate that the Ca2+/Zn2+-dependent gelatinase activities in barnacle nauplii belong to the subfamily of matrix metalloproteases. Barnacle larvae MMPs showed biochemical characteristics different from those of vertebrate MMPs but common to other gelatinases from marine invertebrates: they were unaffected by several protease inhibitors and insensitive to specific activators/inhibitors of vertebrate MMPs. The presence of NIMP-like activities in different naupliar stages suggests a constitutive role for these enzymes in ECM remodeling during barnacle larvae growth and development. (C) 2003 Elsevier Science Inc. All rights reserved.