6BQT

Complex of 14-3-3 theta with an IRSp53 peptide doubly-phosphorylated at T340 and T360

Summary for 6BQT

• Entry DOI: 10.2210/pdb6bqt/pdb
• Related: 6BCR 6BCY
• Descriptor: 14-3-3 protein theta, Insulin receptor substrate protein of 53 kDa, peptide (IRSp53), 2-{2-[2-(2-{2-[2-(2-ETHOXY-ETHOXY)-ETHOXY]-ETHOXY}-ETHOXY)-ETHOXY]-ETHOXY}-ETHANOL, ... (10 entities in total)
• Functional Keywords: phosphate binding protein, protein complex, cytoskeleton regulation, cell motility, signaling protein
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 12
• Total formula weight: 240310.84

Authors

Kast, D.J.,Dominguez, R. (deposition date: 2017-11-28, release date: 2018-12-05, Last modification date: 2024-10-30)

Primary citation

Kast, D.J.,Dominguez, R.
Mechanism of IRSp53 inhibition by 14-3-3.
Nat Commun, 10:483-483, 2019

PubMed Abstract: Filopodia are precursors of dendritic spines and polarized cell migration. The I-BAR-domain protein IRSp53 is a key regulator of filopodia dynamics that couples Rho-GTPase signaling to cytoskeleton and membrane remodeling, playing essential roles in neuronal development and cell motility. Here, we describe the structural-functional basis for 14-3-3-dependent inhibition of IRSp53. Phosphoproteomics, quantitative binding and crystallographic studies demonstrate that 14-3-3 binds to two pairs of phosphorylation sites in IRSp53. Using bicistronic expression, we obtain an IRSp53 heterodimer in which only one subunit is phosphorylated, and show that each subunit of IRSp53 independently binds one 14-3-3 dimer. A FRET-sensor assay using natively phosphorylated IRSp53 reveals opposite conformational changes upon binding of activatory (Cdc42, Eps8) or inhibitory (14-3-3) inputs. Finally, we show that 14-3-3 inhibits IRSp53 binding to membranes. Collectively, our findings support a mechanism whereby phosphorylation-dependent inhibition of IRSp53 by 14-3-3 counters membrane binding and interactions with Cdc42 and downstream cytoskeletal effectors.

PubMed: 30696821
DOI: 10.1038/s41467-019-08317-8

Experimental method

X-RAY DIFFRACTION (2.8 Å)