Specific induction of migration and invasion of pancreatic carcinoma cells by RhoC, which differs from RhoA in its localisation and activity.
RhoA and RhoC are highly related Rho GTPases, but differentially control cellular behaviour. We combined molecular, cellular, and biochemical experiments to characterise differences between these highly similar GTPases. Our findings demonstrate that enhanced expression of RhoC results in a striking increase in the migration and invasion of pancreatic carcinoma cells, whereas forced expression of RhoA decreases these actions. These isoform-specific functions correlate with differences in the cellular activity of RhoA and RhoC in human cells, with RhoC being more active than RhoA in activity assays and serum-response factor-dependent gene transcription. Subcellular localisation studies revealed that RhoC is predominantly localised in the membrane-containing fraction, whereas RhoA is mainly localised in the cytoplasmic fraction. These differences are not mediated by a different interaction with RhoGDIs. In vitro GTP/GDP binding analyses demonstrate different affinity of RhoC for GTP[S] and faster intrinsic and guanine nucleotide exchange factor (GEF)-stimulated GDP/GTP exchange rates compared to RhoA. Moreover, the catalytic domains of SopE and Dbs are efficacious GEFs for RhoC. mRNA expression of RhoC is markedly enhanced in advanced pancreatic cancer stages, and thus the differences discovered between RhoA and RhoC might provide explanations for their different influences on cell migration and tumour invasion.
Dietrich
Karin-Almut
KA
Institute of Pharmacology and Toxicology, University of Ulm, D-89070 Ulm, Germany.
Schwarz
Rene
R
Liska
Martina
M
Grass
Stefanie
S
Menke
Andre
A
Meister
Michael
M
Kierschke
Gesa
G
Längle
Claudia
C
Genze
Felicitas
F
Giehl
Klaudia
K
D045744:Cell Line, Tumor; D002465:Cell Movement; D046690:Deep Brain Stimulation; D006801:Humans; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020668:rap GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000075024:rhoC GTP-Binding Protein
D020033:Protein Isoforms; D012333:RNA, Messenger; C066690:RHOC protein, human; D020668:rap GTP-Binding Proteins; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D000075024:rhoC GTP-Binding Protein