engleski

Aminopeptidase N/CD13 and haematopoietic cells

Several cell-surface antigens defined by the cluster of differentiation (CD) nomenclature have been defined as proteins with enzymatic activity. An important example is CD13, aminopeptidase N (APN ; EC 3.4.11.2). It is a zinc-dependent membrane-bound ectopeptidase that cleaves N-terminal neutral amino acids of various peptides. APN/CD13 has been biochemically characterized, but its crystal structure has not been determined so far. Although conventionally accepted as a myeloid marker, APN/CD13 has recently been detected on lymphocytes as well, following malignant transformation, inflammation or cell activation. Thus, APN/CD13 may be considered a non-lineage antigen, which expression is regulated by differentiation and activation status of haematopoietic cells. APN enzymatic activity represents a cellular potential for activation/inactivation of a variety of known or as yet unknown endogenous peptides. Very recently, additional functional features of APN/CD13 have been demonstrated. It may participate in cell adhesion, cell-cycle control and signal transduction. Since APN/CD13 resides in lipid rafts of haematopoietic cell membranes, it may act in concert with other receptors and signal transducers localized in the rafts. Taken together, high expression of APN/CD13 on haematopoietic cells suggests that it may contribute in very important processes such as cell-cycle control and proliferation, activation, differentiation, transformation, adhesion and signal transduction.

cells; cell membrane rafts; signal transduction; cell cycle

nije evidentirano