Detection of constitutive homomeric associations of the integrins Mac-1 subunits by fluorescence resonance energy transfer in living cells.
Integrins alpha(M)beta(2) plays important role on leukocytes, such as adhesion, migration, phagocytosis, and apoptosis. It was hypothesized that homomeric associations of integrin subunits provide a driving force for integrins activation, and simultaneously inducing the formation of integrins clusters. However, experimental reports on homomeric associations between integrin subunits are still controversial. Here, we proved the homomeric associations of the isolated Mac-1 subunits in living cells using three-channel fluorescence resonance energy transfer (FRET) microscopy and FRET spectra methods. We found that the extent of homomeric associations between beta(2) subunits is higher than alpha(M) subunits. Furthermore, FRET imaging indicated that the extent of homomeric associations of the Mac-1 subunits is higher along the plasma membrane than in the cytoplasm. Finally, we suggested that homomeric associations of the transmembrane domains or/and cytoplasmic domains may provide the driving force for the formation of constitutive homomeric associations between alpha(M) or beta(2) subunits.
Fu
Guo
G
State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
Wang
Chen
C
Wang
Gui-Ying
GY
Chen
Yi-Zhang
YZ
He
Cheng
C
Xu
Zhi-Zhan
ZZ
D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D006801:Humans; D016177:Macrophage-1 Antigen / Q000032:analysis* / Q000235:genetics / Q000378:metabolism*; D008853:Microscopy / Q000379:methods; D021122:Protein Subunits / Q000032:analysis / Q000378:metabolism
D016177:Macrophage-1 Antigen; D021122:Protein Subunits