Structural basis for Ca2+ -dependent formation of ALG-2/Alix peptide complex: Ca2+/EF3-driven arginine switch mechanism

Hironori Suzuki; Masato Kawasaki; Tatsutoshi Inuzuka; Mayumi Okumura; Takeshi Kakiuchi; Hideki Shibata; Soichi Wakatsuki; Masatoshi Maki

doi:10.1016/j.str.2008.07.012

Structural basis for Ca2+ -dependent formation of ALG-2/Alix peptide complex: Ca2+/EF3-driven arginine switch mechanism

Structure. 2008 Oct 8;16(10):1562-73. doi: 10.1016/j.str.2008.07.012.

Authors

Hironori Suzuki¹, Masato Kawasaki, Tatsutoshi Inuzuka, Mayumi Okumura, Takeshi Kakiuchi, Hideki Shibata, Soichi Wakatsuki, Masatoshi Maki

Affiliation

¹ Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.

PMID: 18940611
DOI: 10.1016/j.str.2008.07.012

Abstract

ALG-2 belongs to the penta-EF-hand (PEF) protein family and interacts with various intracellular proteins, such as Alix and TSG101, that are involved in endosomal sorting and HIV budding. Through X-ray crystallography, we solved the structures of Ca(2+)-free and -bound forms of N-terminally truncated human ALG-2 (des3-20ALG-2), Zn(2+)-bound form of full-length ALG-2, and the structure of the complex between des3-23ALG-2 and the peptide corresponding to Alix799-814 in Zn(2+)-bound form. Binding of Ca(2+) to EF3 enables the side chain of Arg125, present in the loop connecting EF3 and EF4, to move enough to make a primary hydrophobic pocket accessible to the critical PPYP motif, which partially overlaps with the GPP motif for the binding of Cep55 (centrosome protein 55 kDa). Based on these results, together with the results of in vitro binding assay with mutant ALG-2 and Alix proteins, we propose a Ca(2+)/EF3-driven arginine switch mechanism for ALG-2 binding to Alix.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Apoptosis Regulatory Proteins / chemistry*
Apoptosis Regulatory Proteins / metabolism*
Arginine / chemistry
Arginine / metabolism*
Binding Sites
Calcium / metabolism
Calcium / pharmacology*
Calcium-Binding Proteins / chemistry*
Calcium-Binding Proteins / metabolism*
Cell Cycle Proteins / chemistry
Cell Cycle Proteins / metabolism*
Crystallography, X-Ray
EF Hand Motifs / physiology*
Endosomal Sorting Complexes Required for Transport
Humans
Models, Molecular
Molecular Sequence Data
Peptide Fragments / chemistry
Peptide Fragments / metabolism
Protein Binding / drug effects
Protein Structure, Tertiary
Sequence Homology, Amino Acid

Substances

Apoptosis Regulatory Proteins
Calcium-Binding Proteins
Cell Cycle Proteins
Endosomal Sorting Complexes Required for Transport
PDCD6 protein, human
PDCD6IP protein, human
Peptide Fragments
Arginine
Calcium

Associated data

PDB/2ZN8
PDB/2ZN9
PDB/2ZND
PDB/2ZNE