Metalloproteinases have been implicated as important factors mediating the tissue migration of a variety of normal and transformed cells. The conditioned medium (CM) of fetal human astrocytes and five glioma cell lines did not degrade azocoll in suspension, but several proteolytic activities, inhibitable by 1,10-phenanthroline, were detected on sodium dodecyl sulfate-polyacrylamide gels contain...

Proteinase species secreted by 10 human gastric carcinoma cell lines were analyzed by gelatin zymography and immunoblotting. These cell lines were classified into the following three groups with respect to proteinase secretion: cell lines secreting mainly gelatinases A and/or B; those secreting multiple types of serine proteinases; and those scarcely secreting these enzymes. Two cell lines of t...

Cystatin C (gamma-trace) was found to be a constitutively secreted protein of isolated human monocytes and mouse peritoneal macrophages, as well as the histiocytic lymphoma cell lines U937, P388D.1, and J774. This proteinase inhibitor is not uniquely secreted by monocytes/macrophages, but was also identified in the conditioned media from several primary cells, including brain cells, and diverse...

Signaling mucins are cell adhesion molecules that activate RAS/RHO guanosine triphosphatases and their effector mitogen-activated protein kinase (MAPK) pathways. We found that the Saccharomyces cerevisiae mucin Msb2p, which functions at the head of the Cdc42p-dependent MAPK pathway that controls filamentous growth, is processed into secreted and cell-associated forms. Cleavage of the extracellu...

Myeloid leukemia cells, the human promyelocytic cell line HL-60, and a subpopulation of normal marrow cells produce a leukemia-associated inhibitor (LAI) that reversibly downmodulates DNA synthesis of normal granulopoietic progenitor cells colony-forming unit granulocyte-macrophage (CFU-GM). We isolated an active 125-kD component of LAI from HL-60 conditioned medium (CM), subjected it to cyanog...

The secreted form of beta-amyloid precursor protein (APP) containing the Kunitz proteinase inhibitor (KPI) domain, also called protease nexin II, is internalized and degraded by cells. We show that the low density lipoprotein (LDL) receptor-related protein (LRP) is responsible for the endocytosis of secreted APP. APPs770 degradation is inhibited by an LRP antagonist called the receptor-associat...