Paxillin phosphorylation controls invadopodia/podosomes spatiotemporal organization.
In Rous sarcoma virus (RSV)-transformed baby hamster kidney (BHK) cells, invadopodia can self-organize into rings and belts, similarly to podosome distribution during osteoclast differentiation. The composition of individual invadopodia is spatiotemporally regulated and depends on invadopodia localization along the ring section: the actin core assembly precedes the recruitment of surrounding integrins and integrin-linked proteins, whereas the loss of the actin core was a prerequisite to invadopodia disassembly. We have shown that invadopodia ring expansion is controlled by paxillin phosphorylations on tyrosine 31 and 118, which allows invadopodia disassembly. In BHK-RSV cells, ectopic expression of the paxillin mutant Y31F-Y118F induces a delay in invadopodia disassembly and impairs their self-organization. A similar mechanism is unraveled in osteoclasts by using paxillin knockdown. Lack of paxillin phosphorylation, calpain or extracellular signal-regulated kinase inhibition, resulted in similar phenotype, suggesting that these proteins belong to the same regulatory pathways. Indeed, we have shown that paxillin phosphorylation promotes Erk activation that in turn activates calpain. Finally, we observed that invadopodia/podosomes ring expansion is required for efficient extracellular matrix degradation both in BHK-RSV cells and primary osteoclasts, and for transmigration through a cell monolayer.
Equipe DySAD, Institut Albert Bonniot, Institut National de la Santé et de la Recherche Médicale U823, 38042 Grenoble Cedex 09, France.
Cédric
C
Badowski
Géraldine
G
Pawlak
Alexei
A
Grichine
Anne
A
Chabadel
Christiane
C
Oddou
Pierre
P
Jurdic
Martin
M
Pfaff
Corinne
C
Albigès-Rizo
Marc R
MR
Block
D000818:Animals; D002154:Calpain / Q000037:antagonists & inhibitors; D002450:Cell Communication / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002472:Cell Transformation, Viral / Q000187:drug effects; D006224:Cricetinae; D004789:Enzyme Activation / Q000187:drug effects; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D050505:Mutant Proteins / Q000378:metabolism; D051419:Paxillin / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011554:Pseudopodia / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D052736:Rous sarcoma virus / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology
D050505:Mutant Proteins; D051419:Paxillin; D010750:Phosphoproteins; D047428:Protein Kinase Inhibitors; D019000:Phosphotyrosine; D014638:Vanadates; D048049:Extracellular Signal-Regulated MAP Kinases; D002154:Calpain