Coactosin-like 1 antagonizes cofilin to promote lamellipodial protrusion at the immune synapse.
Actin depolymerizing factor-homology (ADF-H) family proteins regulate actin filament dynamics at multiple cellular locations. Herein, we have investigated the function of the ADF-H family member coactosin-like 1 (COTL1) in the regulation of actin dynamics at the T cell immune synapse (IS). We initially identified COTL1 in a genetic screen to identify novel regulators of T cell activation, and subsequently found that it associates with F-actin and localizes at the IS in response to TCR+CD28 stimulation. Live cell microscopy showed that depletion of COTL1 protein impaired T cell spreading in response to TCR ligation and abrogated lamellipodial protrusion at the T cell - B cell contact site, producing only a band of F-actin. Significantly, re-expression of wild type COTL1, but not a mutant deficient in F-actin binding could rescue these defects. In addition, COTL1 depletion reduced T cell migration. In vitro studies showed that COTL1 and cofilin compete with each other for binding to F-actin, and COTL1 protects F-actin from cofilin-mediated depolymerization. While depletion of cofilin enhanced F-actin assembly and lamellipodial protrusion at the IS, concurrent depletion of both COTL1 and cofilin restored lamellipodia formation. Taken together, our results suggest that COTL1 regulates lamellipodia dynamics in part by protecting F-actin from cofilin-mediated disassembly.
Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America.
Joanna
J
Kim
Department of Immunology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America.
Michael J
MJ
Shapiro
Department of Molecular Pharmacology and Experimental Therapeutics, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America.
Adebowale O
AO
Bamidele
Department of Biochemistry, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, New Hampshire, United States of America.
Pinar
P
Gurel
Department of Immunology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America.
Puspa
P
Thapa
Department of Biochemistry, Geisel School of Medicine at Dartmouth, Dartmouth College, Hanover, New Hampshire, United States of America.
Henry N
HN
Higgs
Department of Immunology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America.
Karen E
KE
Hedin
Department of Immunology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America.
Virginia S
VS
Shapiro
Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America ; Department of Immunology, College of Medicine, Mayo Clinic, Rochester, Minnesota, United States of America.
Daniel D
DD
Billadeau
D000199:Actins / Q000378:metabolism; D018106:CD28 Antigens / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D018925:Chemokines / Q000494:pharmacology; D051338:Cofilin 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005816:Genetic Complementation Test; D006801:Humans; D054992:Immunological Synapses / Q000187:drug effects / Q000378:metabolism*; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D008840:Microfilament Proteins / Q000378:metabolism*; D011554:Pseudopodia / Q000187:drug effects / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology
D000199:Actins; D018106:CD28 Antigens; C118115:COTL1 protein, human; D018925:Chemokines; D051338:Cofilin 1; D008840:Microfilament Proteins