Structural and mechanistic insights into ras association domains of phospholipase C epsilon.
Ras proteins signal to a number of distinct pathways by interacting with diverse effectors. Studies of ras/effector interactions have focused on three classes, Raf kinases, ral guanylnucleotide-exchange factors, and phosphatidylinositol-3-kinases. Here we describe ras interactions with another effector, the recently identified phospholipase C epsilon (PLCepsilon). We solved structures of PLCepsilon RA domains (RA1 and RA2) by NMR and the structure of the RA2/ras complex by X-ray crystallography. Although the similarity between ubiquitin-like folds of RA1 and RA2 proves that they are homologs, only RA2 can bind ras. Some of the features of the RA2/ras interface are unique to PLCepsilon, while the ability to make contacts with both switch I and II regions of ras is shared only with phosphatidylinositol-3-kinase. Studies of PLCepsilon regulation suggest that, in a cellular context, the RA2 domain, in a mode specific to PLCepsilon, has a role in membrane targeting with further regulatory impact on PLC activity.
Bunney
Tom D
TD
Cancer Research UK Centre for Cell and Molecular Biology, Chester Beatty Laboratories, The Institute of Cancer Research, Fulham Road, London SW3 6JB, United Kingdom.
Harris
Richard
R
Gandarillas
Natalia Lamuño
NL
Josephs
Michelle B
MB
Roe
S Mark
SM
Sorli
S Caroline
SC
Paterson
Hugh F
HF
Rodrigues-Lima
Fernando
F
Esposito
Diego
D
Ponting
Chris P
CP
Gierschik
Peter
P
Pearl
Laurence H
LH
Driscoll
Paul C
PC
Katan
Matilda
M
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D018360:Crystallography, X-Ray; D004789:Enzyme Activation; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D054801:Phosphoinositide Phospholipase C; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology; D013816:Thermodynamics; D010738:Type C Phospholipases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018631:ras Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D011993:Recombinant Fusion Proteins; D010738:Type C Phospholipases; D054801:Phosphoinositide Phospholipase C; C423320:phospholipase C epsilon; D018631:ras Proteins