PMID- 10545207
OWN - NLM
STAT- MEDLINE
DCOM- 19991221
LR  - 20191210
IS  - 0003-9861 (Print)
IS  - 0003-9861 (Linking)
VI  - 371
IP  - 2
DP  - 1999 Nov 15
TI  - Biochemical characterization of the Ras-related GTPases Rit and Rin.
PG  - 207-19
AB  - We report the biochemical characterization of Rit and Rin, two members of the Ras
      superfamily identified by expression cloning. Recombinant Rit and Rin bind GTP
      and exhibit intrinsic GTPase activity. Conversion of Gln to Leu at position 79
      (for Rit) or 78 (for Rin) (equivalent to position 61 in Ras) resulted in a
      complete loss of GTPase activity. Surprisingly, significant differences were
      found when the guanine nucleotide dissociation constants of Rit and Rin were
      compared with the majority of Ras-related GTPases. Both proteins display higher
      k(off) values for GTP than GDP in the presence of 10 mM Mg(2+). These GTP
      dissociation rates are 5- to 10-fold faster than most Ras-like GTPases. Despite
      these unique biochemical properties, our data support the notion that both Rit
      and Rin function as nucleotide-dependent molecular switches. To begin to address 
      whether these proteins act as regulators of distinct signaling pathways, we
      examined their interaction with a series of known Ras-binding proteins by yeast
      two-hybrid analysis. Although Rit, Rin, and Ras have highly related effector
      domain sequences, Rit and Rin were found to interact with the known Ras binding
      proteins RalGDS, Rlf, and AF-6/Canoe but not with the Raf kinases, RIN1, or the
      p110 subunit of phosphatidylinositol 3-kinase. These interactions were GTP and
      effector domain dependent and suggest that RalGDS, Rlf, and AF-6 are Rit and Rin 
      effectors. Their biochemical properties and interaction with a subset of known
      Ras effector proteins suggest that Rit and Rin may play important roles in the
      regulation of signaling pathways and cellular processes distinct from those
      controlled by Ras.
CI  - Copyright 1999 Academic Press.
FAU - Shao, H
AU  - Shao H
AD  - Department of Biochemistry, University of Kentucky College of Medicine,
      Lexington, Kentucky 40536-0084, USA.
FAU - Kadono-Okuda, K
AU  - Kadono-Okuda K
FAU - Finlin, B S
AU  - Finlin BS
FAU - Andres, D A
AU  - Andres DA
LA  - eng
SI  - GENBANK/AF084462
SI  - GENBANK/AF084463
GR  - EY11231/EY/NEI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Arch Biochem Biophys
JT  - Archives of biochemistry and biophysics
JID - 0372430
RN  - 0 (AFDN protein, human)
RN  - 0 (Afdn protein, mouse)
RN  - 0 (Guanine Nucleotides)
RN  - 0 (RLF protein, human)
RN  - 0 (Recombinant Proteins)
RN  - 0 (Rgl2 protein, mouse)
RN  - 0 (Transcription Factors)
RN  - 0 (ral Guanine Nucleotide Exchange Factor)
RN  - 146-91-8 (Guanosine Diphosphate)
RN  - 37589-80-3 (Guanosine 5'-O-(3-Thiotriphosphate))
RN  - 86-01-1 (Guanosine Triphosphate)
RN  - EC 3.6.1.- (RIT1 protein, human)
RN  - EC 3.6.1.- (Rin protein (GTPase))
RN  - EC 3.6.4.1 (Myosins)
RN  - EC 3.6.4.4 (Kinesin)
RN  - EC 3.6.5.2 (ras Proteins)
SB  - IM
MH  - Cloning, Molecular
MH  - Guanine Nucleotides/*metabolism
MH  - Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
MH  - Guanosine Diphosphate/metabolism
MH  - Guanosine Triphosphate/metabolism
MH  - Humans
MH  - Hydrolysis
MH  - Kinesin/metabolism
MH  - Molecular Sequence Data
MH  - Myosins/metabolism
MH  - Protein Binding
MH  - Recombinant Proteins/metabolism
MH  - Signal Transduction
MH  - Transcription Factors/metabolism
MH  - Two-Hybrid System Techniques
MH  - ral Guanine Nucleotide Exchange Factor/metabolism
MH  - ras Proteins/genetics/*metabolism
EDAT- 1999/11/05 00:00
MHDA- 1999/11/05 00:01
CRDT- 1999/11/05 00:00
PHST- 1999/11/05 00:00 [pubmed]
PHST- 1999/11/05 00:01 [medline]
PHST- 1999/11/05 00:00 [entrez]
AID - 10.1006/abbi.1999.1448 [doi]
AID - S0003-9861(99)91448-0 [pii]
PST - ppublish
SO  - Arch Biochem Biophys. 1999 Nov 15;371(2):207-19. doi: 10.1006/abbi.1999.1448.