Tyr-317 phosphorylation increases Shc structural rigidity and reduces coupling of domain motions remote from the phosphorylation site as revealed by molecular dynamics simulations.
Activated receptor tyrosine kinases bind the Shc adaptor protein through its N-terminal phosphotyrosine-binding (PTB) and C-terminal Src homology 2 (SH2) domains. After binding, Shc is phosphorylated within the central collagen-homology (CH) linker region on Tyr-317, a residue remote to both the PTB and SH2 domains. Shc phosphorylation plays a pivotal role in the initiation of mitogenic signaling through the Ras/Raf/MEK/ERK pathway, but it is unclear if Tyr-317 phosphorylation affects Shc-receptor interactions through the PTB and SH2 domains. To investigate the structural impact of Shc phosphorylation, molecular dynamics simulations were carried out using special-purpose Molecular Dynamics Machine-Grape computers. After a 1-nanosecond equilibration, atomic motions in the structures of unphosphorylated Shc and Shc phosphorylated on Tyr-317 were calculated during a 2-nanosecond period. The results reveal larger phosphotyrosine-binding domain fluctuations and more structural flexibility of unphosphorylated Shc compared with phosphorylated Shc. Collective motions between the PTB-SH2, PTB-CH, and CH-SH2 domains were highly correlated only in unphosphorylated Shc. Dramatic changes in domain coupling and structural rigidity, induced by Tyr-317 phosphorylation, may alter Shc function, bringing about marked differences in the association of unphosphorylated and phosphorylated Shc with its numerous partners, including activated membrane receptors.
Suenaga
Atsushi
A
Bioinformatics Group, RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
Kiyatkin
Anatoly B
AB
Hatakeyama
Mariko
M
Futatsugi
Noriyuki
N
Okimoto
Noriaki
N
Hirano
Yoshinori
Y
Narumi
Tetsu
T
Kawai
Atsushi
A
Susukita
Ryutaro
R
Koishi
Takahiro
T
Furusawa
Hideaki
H
Yasuoka
Kenji
K
Takada
Naoki
N
Ohno
Yousuke
Y
Taiji
Makoto
M
Ebisuzaki
Toshikazu
T
Hoek
Jan B
JB
Konagaya
Akihiko
A
Kholodenko
Boris N
BN
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D066298:In Vitro Techniques; D008958:Models, Molecular; D010766:Phosphorylation; D011487:Protein Conformation; D055765:Shc Signaling Adaptor Proteins; D013816:Thermodynamics; D014443:Tyrosine / Q000737:chemistry; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D055765:Shc Signaling Adaptor Proteins; D014443:Tyrosine