Dynamic phosphoproteomics of insulin and epidermal growth factor signaling in mouse hepatocytes

Youping LIU; Fuli YAO; Huirong DING; Hong LI

ABSTRACT

BACKGROUND:

Both epidermal growth factor (EGF) and insulin transfer their signals into cells by two primary signal transduction pathways,including phosphatidylinositol 3-kinase (PI3K) pathway and mitogen activated protein kinases (MAPK) pathway.But they have different physiological functions.

OBJECTIVE:

To comparatively assay the dynamic behaviors of phosphoproteomes between EGF and insulin signal transductions in mouse hepatocytes and find key signal proteins.DESIGN,TIME AND

SETTING:

Randomized grouping controlled observation experiment was performed in the laboratory of Molecular Biology,Luzhou Medical College between July 2005 and April 2006.MATERIALS Hepatocytes were from Kunming mice of closed population.

METHODS:

The primarily cultured mouse hepatocytes were labeled with 32p isotope and then randomly divided into three groups control,EGF-stimulated (received 10 μg/L EGF),and insulin-stimulated (received 100 nmol/L insulin) groups.MAIN OUTCOME

MEASURES:

After mouse hepatocytes were treated with EGF and insulin for 0,5,20,60 and 120 minutes,the dynamic behaviors of phosphoproteomes(I.e,phosphorylated level) between EGF and insulin signal transductions were comparatively analyzed by two-dimensional electrophoresis method.

RESULTS:

The categories of all phosphorylated proteins between EGF and insulin-stimulated phosphoproteomes had no apparent difference.The dynamic behaviors of phosphoproteomes of most proteins during EGF signal transduction are parallel with those during insulin stimulation,except the dynamic behaviors of 4 proteins are different significantly.

CONCLUSION:

Aforementioned 4 phosphorylated proteins were most probably the key members that could distinguish between two signal transduction pathways ornetworks,and determined their major physiological functions respectively.