Requirements for F-BAR proteins TOCA-1 and TOCA-2 in actin dynamics and membrane trafficking during Caenorhabditis elegans oocyte growth and embryonic epidermal morphogenesis.
The TOCA family of F-BAR-containing proteins bind to and remodel lipid bilayers via their conserved F-BAR domains, and regulate actin dynamics via their N-Wasp binding SH3 domains. Thus, these proteins are predicted to play a pivotal role in coordinating membrane traffic with actin dynamics during cell migration and tissue morphogenesis. By combining genetic analysis in Caenorhabditis elegans with cellular biochemical experiments in mammalian cells, we showed that: i) loss of CeTOCA proteins reduced the efficiency of Clathrin-mediated endocytosis (CME) in oocytes. Genetic interference with CeTOCAs interacting proteins WSP-1 and WVE-1, and other components of the WVE-1 complex, produced a similar effect. Oocyte endocytosis defects correlated well with reduced egg production in these mutants. ii) CeTOCA proteins localize to cell-cell junctions and are required for proper embryonic morphogenesis, to position hypodermal cells and to organize junctional actin and the junction-associated protein AJM-1. iii) Double mutant analysis indicated that the toca genes act in the same pathway as the nematode homologue of N-WASP/WASP, wsp-1. Furthermore, mammalian TOCA-1 and C. elegans CeTOCAs physically associated with N-WASP and WSP-1 directly, or WAVE2 indirectly via ABI-1. Thus, we propose that TOCA proteins control tissues morphogenesis by coordinating Clathrin-dependent membrane trafficking with WAVE and N-WASP-dependent actin-dynamics.
The FIRC Institute for Molecular Oncology, Milan, Italy.
Chiara
C
Giuliani
Flavia
F
Troglio
Zhiyong
Z
Bai
Falshruti B
FB
Patel
Adriana
A
Zucconi
Maria Grazia
MG
Malabarba
Andrea
A
Disanza
Theresia B
TB
Stradal
Giuseppe
G
Cassata
Stefano
S
Confalonieri
Jeffrey D
JD
Hardin
Martha C
MC
Soto
Barth D
BD
Grant
Giorgio
G
Scita
D000199:Actins / Q000378:metabolism*; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D004817:Epidermis / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism; D005260:Female; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009024:Morphogenesis; D009865:Oocytes / Q000254:growth & development* / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport
D000199:Actins; D029742:Caenorhabditis elegans Proteins; D008565:Membrane Proteins; C545960:TOCA-1 protein, C elegans; C545961:TOCA-2 protein, C elegans; C532812:wsp-1 protein, C elegans