Site-directed Mutagenesis Shows the Significance of Interactions with Phospholipids and the G-protein OsYchF1 for the Physiological Functions of the Rice GTPase-activating Protein 1 (OsGAP1).
The C2 domain is one of the most diverse phospholipid-binding domains mediating cellular signaling. One group of C2-domain proteins are plant-specific and are characterized by their small sizes and simple structures. We have previously reported that a member of this group, OsGAP1, is able to alleviate salt stress and stimulate defense responses, and bind to both phospholipids and an unconventional G-protein, OsYchF1. Here we solved the crystal structure of OsGAP1 to a resolution of 1.63 Å. Using site-directed mutagenesis, we successfully differentiated between the clusters of surface residues that are required for binding to phospholipids versus OsYchF1, which, in turn, is critical for its role in stimulating defense responses. On the other hand, the ability to alleviate salt stress by OsGAP1 is dependent only on its ability to bind OsYchF1 and is independent of its phospholipid-binding activity.
From the School of Life Sciences, Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology, and.
Yuk-Lin
YL
Yung
From the School of Life Sciences, Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology, and.
Ming-Yan
MY
Cheung
From the School of Life Sciences, Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology, and the School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China.
Rui
R
Miao
From the School of Life Sciences, Center for Protein Sciences and Crystallography, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China and.
Yu-Hang
YH
Fong
From the School of Life Sciences, Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology, and.
Kwan-Pok
KP
Li
From the School of Life Sciences, Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology, and.
Mei-Hui
MH
Yu
the School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China.
Mee-Len
ML
Chye
From the School of Life Sciences, Center for Protein Sciences and Crystallography, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China and.
Kam-Bo
KB
Wong
From the School of Life Sciences, Centre for Soybean Research of the Partner State Key Laboratory of Agrobiotechnology, and honming@cuhk.edu.hk.
Hon-Ming
HM
Lam
D018360:Crystallography, X-Ray; D016297:Mutagenesis, Site-Directed; D012275:Oryza / Q000201:enzymology* / Q000235:genetics; D010743:Phospholipids / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D020703:ras GTPase-Activating Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D010743:Phospholipids; D010940:Plant Proteins; D020703:ras GTPase-Activating Proteins
G protein; crystal structure; phospholipid; plant defense; plasma membrane