ABSTRACT
Moonlighting proteins exhibit multiple activities in different cellular compartments, and their abnormal regulation could play an important role in many diseases. To date, many proteins have been identified with moonlighting activity, and more such proteins are being gradually identified. Among the proteins that possess moonlighting activity, several secreted proteins exhibit multiple activities in different cellular locations, such as the extracellular matrix, nucleus, and cytoplasm. While acute inflammation starts rapidly and generally disappears in a few days, chronic inflammation can last for months or years. This is generally because of the failure to eliminate the cause of inflammation, along with repeated exposure to the inflammatory agent. Chronic inflammation is now considered as an overwhelming burden to the general wellbeing of patients and noted as an underlying cause of several diseases. Moonlighting proteins can contribute to the process of chronic inflammation; therefore, it is imperative to overview some proteins that exhibit multiple functions in inflammatory diseases. In this review, we will focus on inflammation, particularly unravelling several well-known secreted proteins with multiple functions in different cellular locations.
Subject(s)
Humans , Cytoplasm , Extracellular Matrix , InflammationABSTRACT
La Ceruloplasmina (Cp) es la principal proteína transportadora de cobre en circulación. Su concentración es abundante en plasma; se considera un reactante de fase aguda y su función fisiológica no se encuentra fehacientemente establecida. Fundamentalmente se sintetiza en los hepatocitos. También se encuentra en otros tipos celulares como monocitos, astrocitos y células de Sertoli. Su concentración sérica se utiliza en el diagnóstico diferencial de enfermedad de Wilson. La concentración total en plasma se considera igual a la suma de las concentraciones de apo y holo Cp, de manera que la cantidad de esta proteína determinada por un método inmunológico no indica que la enzima se encuentre presente solamente en su forma activa. Entonces, al utilizar esta metodología, se sobreestima la proteína funcionalmente activa. Existen diversos métodos para determinar su actividad. En este trabajo se describe un método automatizado para medir su actividad ferroxidasa que utiliza iones Fe2+ como sustrato. Los valores de referencia de actividad de Cp se diferenciaron estadísticamente entre el grupo de mujeres y el de hombres, siendo de 424-796 UI/L y 397-733 UI/L, respectivamente. Además, se obtuvo una correlación significativa entre la actividad ferroxidasa y la concentración proteica (r=0,7285; p<0,0001).
Ceruloplasmin (Cp) is the principal copper carrier in human plasma. It is an abundant protein that participates in the acute phase reaction to stress, but its physiological function is unknown. Althought Cp is synthesised predominantly in the liver, other cell types express the protein, including monocytes, astrocytes and Sertoli cells. The serum concentration of the copper protein ceruloplasmin has been an important diagnostic indicator of Wilson`s disease. Measurement of the total amount of Cp protein may not reflect Cp enzyme activity in the serum. The immunologic assay may lead to overestimation of the total amount of functional Cp in the serum due to this method's capacity to determine both the functional holo Cp and non-functional apo Cp. Several methods for determining ferroxidase activity have been reported. In this study, a method is described for automated measurement of the activity. In this method, Fe2+ ions are used as the substrate. The range for serum Cp ferroxidase activity in healthy persons was 424-796 UI/L for women, and 397-733 UI/L for men. Significant correlations between serum ferroxidase activity and Cp concentration (r=0,7285; p < 0,0001) were found.