The talin head domain reinforces integrin-mediated adhesion by promoting adhesion complex stability and clustering.
Talin serves an essential function during integrin-mediated adhesion in linking integrins to actin via the intracellular adhesion complex. In addition, the N-terminal head domain of talin regulates the affinity of integrins for their ECM-ligands, a process known as inside-out activation. We previously showed that in Drosophila, mutating the integrin binding site in the talin head domain resulted in weakened adhesion to the ECM. Intriguingly, subsequent studies showed that canonical inside-out activation of integrin might not take place in flies. Consistent with this, a mutation in talin that specifically blocks its ability to activate mammalian integrins does not significantly impinge on talin function during fly development. Here, we describe results suggesting that the talin head domain reinforces and stabilizes the integrin adhesion complex by promoting integrin clustering distinct from its ability to support inside-out activation. Specifically, we show that an allele of talin containing a mutation that disrupts intramolecular interactions within the talin head attenuates the assembly and reinforcement of the integrin adhesion complex. Importantly, we provide evidence that this mutation blocks integrin clustering in vivo. We propose that the talin head domain is essential for regulating integrin avidity in Drosophila and that this is crucial for integrin-mediated adhesion during animal development.
Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.
Stephanie J
SJ
Ellis
Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.
Emily
E
Lostchuck
School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom.
Benjamin T
BT
Goult
Department of Pharmacology, Yale University, New Haven, Connecticut, United States of America; Carnegie Mellon University Qatar, Education City, Doha, Qatar.
Mohamed
M
Bouaouina
Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.
Michael J
MJ
Fairchild
Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.
Pablo
P
López-Ceballos
Department of Pharmacology, Yale University, New Haven, Connecticut, United States of America.
David A
DA
Calderwood
Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.
Guy
G
Tanentzapf
D000483:Alleles; D000818:Animals; D002448:Cell Adhesion / Q000235:genetics*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000196:embryology; D004625:Embryo, Nonmammalian; D047108:Embryonic Development / Q000235:genetics*; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism; D036681:Fluorescence Recovery After Photobleaching; D016023:Integrins / Q000235:genetics* / Q000378:metabolism; D017354:Point Mutation; D017434:Protein Structure, Tertiary; D016608:Talin / Q000235:genetics* / Q000378:metabolism
D016023:Integrins; D016608:Talin