The GTPase-activating protein RN-tre controls focal adhesion turnover and cell migration.
BACKGROUND
Integrin-mediated adhesion of cells to the extracellular matrix (ECM) relies on the dynamic formation of focal adhesions (FAs), which are biochemical and mechanosensitive platforms composed of a large variety of cytosolic and transmembrane proteins. During migration, there is a constant turnover of ECM contacts that initially form as nascent adhesions at the leading edge, mature into FAs as actomyosin tension builds up, and are then disassembled at the cell rear, thus allowing for cell detachment. Although the mechanisms of FA assembly have largely been defined, the molecular circuitry that regulates their disassembly still remains elusive.


RESULTS
Here, we show that RN-tre, a GTPase-activating protein (GAP) for Rabs including Rab5 and Rab43, is a novel regulator of FA dynamics and cell migration. RN-tre localizes to FAs and to a pool of Rab5-positive vesicles mainly associated with FAs undergoing rapid remodeling. We found that RN-tre inhibits endocytosis of β1, but not β3, integrins and delays the turnover of FAs, ultimately impairing β1-dependent, but not β3-dependent, chemotactic cell migration. All of these effects are mediated by its GAP activity and rely on Rab5.


CONCLUSIONS
Our findings identify RN-tre as the Rab5-GAP that spatiotemporally controls FA remodeling during chemotactic cell migration.
IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milano, Italy.
Andrea
A
Palamidessi
Emanuela
E
Frittoli
Nadia
N
Ducano
Nina
N
Offenhauser
Sara
S
Sigismund
Hiroaki
H
Kajiho
Dario
D
Parazzoli
Amanda
A
Oldani
Marco
M
Gobbi
Guido
G
Serini
Pier Paolo
PP
Di Fiore
Giorgio
G
Scita
Letizia
L
Lanzetti
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000235:genetics*; D002478:Cells, Cultured; D004318:Doxycycline / Q000494:pharmacology; D004705:Endocytosis / Q000235:genetics* / Q000502:physiology; D022001:Focal Adhesions / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D019012:Integrin beta1 / Q000378:metabolism; D039661:Integrin beta3 / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D034622:RNA Interference; D034741:RNA, Small Interfering; D015398:Signal Transduction / Q000502:physiology; D020691:rab GTP-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D020696:rab5 GTP-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D000099193:rab11 GTP-Binding Proteins
D048868:Adaptor Proteins, Signal Transducing; D004318:Doxycycline; D020690:GTPase-Activating Proteins; D019012:Integrin beta1; D039661:Integrin beta3; D034741:RNA, Small Interfering; D020691:rab GTP-Binding Proteins; D020696:rab5 GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C000590733:Usp6nl protein, Mouse; C561704:Rab30 protein, mouse