CW-EPR studies revealed different motional properties and oligomeric states of the integrin β1a transmembrane domain in detergent micelles or liposomes
| Autor: | Lu Yu, Shenglong Ling, Chaohua Lai, Changlin Tian, Ying Xiong, Liang Xiao, Longhua Zhang, Sanling Liu, Yanlong Xin, Wei Wang |
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| Rok vydání: | 2014 |
| Předmět: |
Circular dichroism
Integrin Detergents Molecular Sequence Data Micelle Protein Structure Secondary Article Humans Amino Acid Sequence Micelles Liposome Multidisciplinary biology Chemistry Extracellular matrix assembly Circular Dichroism Integrin beta1 Electron Spin Resonance Spectroscopy Site-directed spin labeling Transmembrane protein Protein Structure Tertiary Transmembrane domain Biochemistry Liposomes biology.protein Biophysics |
| Zdroj: | Scientific Reports |
| ISSN: | 2045-2322 |
| Popis: | Integrins are heterodimeric membrane proteins that regulate essential processes: cell migration, cell growth, extracellular matrix assembly and tumor metastasis. Each integrin α or β subunit contains a large extracellular domain, a single transmembrane (TM) domain, and a short cytoplasmic tail. The integrin TM domains are important for heterodimeric association and dissociation during the conversion from inactive to active states. Moreover, integrin clustering occurs by homo-oligomeric interactions between the TM helices. Here, the transmembrane and cytoplasmic (TMC) domains of integrin β1a were overexpressed, and the protein was purified in detergent micelles and/or reconstituted in liposomes. To investigate the TM domain conformational properties of integrin β1a, 26 consecutive single cysteine mutants were generated for site-directed spin labeling and continuous-wave electron paramagnetic resonance (CW-EPR) mobility and accessibility analyses. The mobility analysis identified two integrin β1a-TM regions with different motional properties in micelles and a non-continuous integrin β1a-TM helix with high immobility in liposomes. The accessibility analysis verified the TM range (Val737-Lys752) of the integrin β1a-TMC in micelles. Further mobility and accessibility comparisons of the integrin β1a-TMC domains in micelles or liposomes identified distinctively different oligomeric states of integrin β1a-TM, namely a monomer embedded in detergent micelles and leucine-zipper-like homo-oligomeric clusters in liposomes. |
| Databáze: | OpenAIRE |
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