A new nuclear protease with cathepsin L properties is present in HeLa and Caco-2 cells.
Recently many authors have reported that cathepsin L can be found in the nucleus of mammalian cells with important functions in cell-cycle progression. In previous research, we have demonstrated that a cysteine protease (SpH-protease) participates in male chromatin remodeling and in cell-cycle progression in sea urchins embryos. The gene that encodes this protease was cloned. It presents a high identity sequence with cathepsin L family. The active form associated to chromatin has a molecular weight of 60 kDa, which is higher than the active form of cathepsin L described until now, which range between 25 and 35 kDa. Another difference is that the zymogen present in sea urchin has a molecular weight of 75 and 90 kDa whereas for human procathepsin L has a molecular weight of 38-42 kDa. Based on these results and using a polyclonal antibody available in our laboratory that recognizes the active form of the 60 kDa nuclear cysteine protease of sea urchin, ortholog to human cathepsin L, we investigated the presence of this enzyme in HeLa and Caco-2 cells. We have identified a new nuclear protease, type cathepsin L, with a molecular size of 60 kDa, whose cathepsin activity increases after a partial purification by FPLC and degrade in vitro histone H1. This protease associates to the mitotic spindle during mitosis, remains in the nuclei in binuclear cells and also translocates to the cytoplasm in non-proliferative cells.
Puchi
Marcia
M
Department of Biochemistry and Molecular Biology, Universidad de Concepcion, P.O. Box 160-C, Concepcion, Chile.
García-Huidobro
Jenaro
J
Cordova
Candy
C
Aguilar
Rodrigo
R
Dufey
Estefanie
E
Imschenetzky
Maria
M
Bustos
Paula
P
Morin
Violeta
V
D021581:Active Transport, Cell Nucleus; D000818:Animals; D018938:Caco-2 Cells / Q000201:enzymology*; D056668:Cathepsin L; D002453:Cell Cycle; D003001:Cloning, Molecular; D057056:Cysteine Proteases / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D005260:Female; D006367:HeLa Cells / Q000201:enzymology*; D006801:Humans; D008297:Male; D009687:Nuclear Proteins / Q000032:analysis; D012617:Sea Urchins / Q000201:enzymology*; D017385:Sequence Homology; D008941:Spindle Apparatus / Q000378:metabolism
D009687:Nuclear Proteins; D057056:Cysteine Proteases; D056668:Cathepsin L