TMD1 domain and CRAC motif determine the association and disassociation of MxIRT1 with detergent‐resistant membranes |
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| Authors: | Song Tan Peng Zhang Wei Xiao Bing Feng Lan‐You Chen Shuang Li Peng Li Wei‐Zhong Zhao Xiao‐Ting Qi Li‐Ping Yin |
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| Institution: | 1. College of Life Science, Capital Normal University, Beijing, China;2. State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China;3. Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada;4. School of Life Sciences, Tsinghua University, Beijing, China;5. School of Mathematical Sciences, Capital Normal University, Beijing, China |
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| Abstract: | Iron is essential for most living organisms. The iron‐regulated transporter1 (IRT1) plays a major role in iron uptake in roots, and its trafficking from endoplasmic reticulum (ER) to plasma membrane (PM) is tightly coordinated with changes in iron environment. However, studies on the IRT1 response are limited. Here, we report that Malus xiaojinesis IRT1 (MxIRT1) associates with detergent‐resistant membranes (DRMs, a biochemical counterpart of PM microdomains), whereas the PM microdomains are known platforms for signal transduction in the PM. Depending on the shift of MxIRT1 from microdomains to homogeneous regions in PM, MxIRT1‐mediated iron absorption is activated by the cholesterol recognition/interaction amino acid consensus (CRAC) motif of MxIRT1. MxIRT1 initially associates with DRMs in ER via its transmembrane domain 1 (TMD1), and thus begins DRMs‐dependent intracellular trafficking. Subsequently, MxIRT1 is sequestered in COPII vesicles via the ER export signal sequence in MxIRT1. These studies suggest that iron homeostasis is influenced by the CRAC motif and TMD1 domain due to their determination of MxIRT1‐DRMs association.  |
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| Keywords: | CRAC motif detergent‐resistant membranes intracellular trafficking iron MxIRT1 TMD1 |
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