Proteomic characterization of human milk fat globule membrane proteins during a 12 month lactation period.

The milk fat globule membrane (MFGM) contains proteins which have been implicated in a variety of health benefits. Milk fat globule membrane proteins were isolated from human milk during a 12 month lactation period and subjected to in-solution digestion and liquid chromatography tandem mass spectrometry analysis. Data were pooled, and our results showed that 191 proteins were identified. Relative quantification of the identified MFGM proteins during the course of lactation was performed by label free spectral counting and differentiation expression analysis, which showed some proteins decreasing during the course of lactation whereas some increased or remained at a relatively constant level. The human MFGM proteins are distributed between intracellular, extracellular, and membrane-associated proteins, and they are mainly involved in cell communication and signal transduction, immune function, metabolism and energy production. This study provides more insights into the dynamic composition of human MFGM proteins, which in turn will enhance our understanding of the physiological significance of MFGM proteins.