Interaction Analyses of 14-3-3ζ, Dok1, and Phosphorylated Integrin β Cytoplasmic Tails Reveal a Bi-molecular Switch in Integrin Regulation

JOURNAL OF MOLECULAR BIOLOGY

卷:430

Article

Chatterjee, Deepak¹  D'Souza, Areetha¹  Zhang, Yaming^1,2  Bin, Wu^1,2  Tan, Suet-Mien¹  Bhattacharjya, Surajit^1,2 

[1] Nanyang Technol Univ, Sch Biol Sci, 60 Nanyang Dr, Singapore 637551, Singapore

[2] Nanyang Technol Univ, Inst Biol Struct, 59 Nanyang Dr, Singapore 636921, Singapore

关键词: integrins;    NMR;    protein-protein interaction;    14-3-3;    Dok1;   

DOI  :  10.1016/j.jmb.2018.09.008

来源: Elsevier

【 摘 要 】

Integrins are hetero-dimeric (alpha and beta subunits) type I transmembrane proteins that facilitate cell adhesion and migration. The cytoplasmic tails (CTs) of integrins interact with a plethora of intra-cellular proteins that are required for integrin bidirectional signaling. In particular, the beta CTs of integrins are known to recruit a variety of cytosolic proteins that often have overlapping recognition sites. However, the chronological sequence of beta CTs/cytosolic proteins interactions remains to be fully characterized. Previous studies have shown that the scaffold protein 14-3-3 zeta binds to phosphorylated beta CTs in activated integrins, whereas interactions of Dok-1 with phosphorylated beta CTs maintained integrins in the resting state. In this study, we examined the binding interactions between 14-3-3 zeta, Dok1, and phosphorylated integrin beta 2 and beta 3 CTs. We show that the scaffold protein 14-3-3 zeta interacts with the phosphotyrosine binding (PTB) domain of Dok1 even in the absence of the phosphorylated integrin beta CTs. The interactions were mapped onto the beta-sheet region of the PTB domain of Dok1. Furthermore, we provide evidence that the 14-3-3 zeta/Dok1 binary complex is able to bind to their cognate phosphorylated sequence motifs in the integrin beta CTs. We demonstrate that Thr phosphorylated pTTT beta 2 CT or pTST beta 3 CT can bind to 14-3-3 zeta that is in complex with the Dok1 PTB domain, whereas Ser phosphorylated beta 2 CT or Tyr phosphorylated beta 3 CT interacted with Dok1 in 14-3-3 zeta/Dok1 complex. Based on these data, we propose that 14-3-3 zeta/Dok1 complex could serve as a molecular switch providing novel molecular insights into the regulating integrin activation. (C) 2018 Elsevier Ltd. All rights reserved.

【 授权许可】

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