Comparative proteomic analysis of a cytosolic fraction from β3 integrin-deficient cells.
Integrins are heterodimeric transmembrane receptors involved in sensing and transmitting informational cues from the extracellular environment to the cell. This study explored sub-proteome changes in response to elimination of the β3 integrin using a knockout murine model. Cleavable isotope-coded affinity tagging (cICAT) in combination with sub-cellular fractionation, multiple dimensions of separation and tandem mass spectrometry (MS/MS) were used to characterize differentially expressed proteins among β3 integrin(-/-) (β3(-/-)) mouse embryonic fibroblasts and isogenic wild-type (WT) controls. From a cytosolic protein fraction, 48 proteins were identified, in which expression differed by > 1.5-fold. Predominant ontological groups included actin-binding/cytoskeletal proteins and protease/protease inhibitors. Interestingly, β3 integrin expression was inversely correlated with expression of cathepsin B, a lysosomal cysteine protease, as its expression was greater by over 3.5-fold in the β3(-/-) cells. This inverse correlation was also observed in stable heterologous cells transfected with β3 integrin, where the intracellular expression and activity of cathepsin B was lower compared to control cells. Our data suggests that the composition of the cellular proteome is influenced by integrin expression patterns and reveals a strong functional relationship between β3 integrin and cathepsin B.
Biology Department,College of Science and Mathematics, California State University-Fresno, 2555 E. Ramon Ave., M/S SB73, Fresno, CA 93740, USA. jbush@csufresno.edu
Jason A
JA
Bush
Hideki
H
Kitaura
Yuliang
Y
Ma
Steven L
SL
Teitelbaum
F Patrick
FP
Ross
Jeffrey W
JW
Smith
D000818:Animals; D002401:Cathepsin B / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D039661:Integrin beta3 / Q000235:genetics*; D007553:Isotope Labeling; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D051419:Paxillin / Q000378:metabolism; D011485:Protein Binding; D020543:Proteome / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D053719:Tandem Mass Spectrometry; D014162:Transfection
D039661:Integrin beta3; D051419:Paxillin; D020543:Proteome; D002401:Cathepsin B