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.
Cancer Research UK Centre for Cell and Molecular Biology, Chester Beatty Laboratories, The Institute of Cancer Research, Fulham Road, London SW3 6JB, United Kingdom.
Tom D
TD
Bunney
Richard
R
Harris
Natalia Lamuño
NL
Gandarillas
Michelle B
MB
Josephs
S Mark
SM
Roe
S Caroline
SC
Sorli
Hugh F
HF
Paterson
Fernando
F
Rodrigues-Lima
Diego
D
Esposito
Chris P
CP
Ponting
Peter
P
Gierschik
Laurence H
LH
Pearl
Paul C
PC
Driscoll
Matilda
M
Katan
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