Morpholino knockdown of lysyl oxidase impairs zebrafish development, and reflects some aspects of copper metabolism disorders.

Lysyl oxidase (LOX), a copper-dependent amine oxidase known in mammals to catalyze the cross-linking of collagen and elastin in the extracellular matrix, is a member of a multigenic family. Eight genes encoding lysyl oxidase isoforms have been identified in zebrafish. Recent studies have revealed a critical role for two zebrafish lysyl oxidases-like in the formation of the notochord.

The lysyl oxidase LOX is absent in basal and squamous cell carcinomas and its knockdown induces an invading phenotype in a skin equivalent model.

Lysyl oxidase initiates the enzymatic stage of collagen and elastin cross-linking. Among five isoforms comprising the lysyl oxidase family, LOX is the better studied. LOX is associated to an antitumor activity in ras-transformed fibroblasts, and its expression is down-regulated in many carcinomas.

The Pro-regions of lysyl oxidase and lysyl oxidase-like 1 are required for deposition onto elastic fibers.

These studies were undertaken to determine how lysyl oxidase (LOX) and lysyl oxidase like-1 (LOXL) enzymes are targeted to their substrates in the extracellular matrix. Full-length LOX/LOXL and constructs containing just the pro-regions of each enzyme localized to elastic fibers when expressed in cultured cells. However, the LOXL catalytic domain without the pro-region was secreted into the medium but did not associate with matrix.

Lysyl oxidase-like and lysyl oxidase are present in the dermis and epidermis of a skin equivalent and in human skin and are associated to elastic fibers.

Elastic fiber formation involves the secretion of tropoelastin which is converted to insoluble elastin by cross-linking, initiated by the oxidative deamination of lysine residues by lysyl oxidase. Five lysyl oxidase genes have been discovered. This study deals with the expression of two isoforms, LOX and LOX-like (LOXL), in human foreskin and in a human skin-equivalent (SE) model that allows the formation of elastic fibers.

Expression analysis of recombinant lysyl oxidase (LOX) in myofibroblastlike cells.

Lysyl oxidase (LOX), originally known as the enzyme required for initiation of covalent cross-linking in collagens and elastin, is now known to be a member of a family of genetically related proteins. LOX, or a related protein, has also been localized intracellularly, both in association with the cytoskeleton and in the cell nucleus. To determine the structural requirements for secretion, maturation, and nuclear location of LOX in a cellular context, we have devised an homologous cell model for expression of the recombinant protein.