LIM kinase 1 and cofilin regulate actin filament population required for dynamin-dependent apical carrier fission from the trans-Golgi network.
The functions of the actin cytoskeleton in post-Golgi trafficking are still poorly understood. Here, we report the role of LIM Kinase 1 (LIMK1) and its substrate cofilin in the trafficking of apical and basolateral proteins in Madin-Darby canine kidney cells. Our data indicate that LIMK1 and cofilin organize a specialized population of actin filaments at the Golgi complex that is selectively required for the emergence of an apical cargo route to the plasma membrane (PM). Quantitative pulse-chase live imaging experiments showed that overexpression of kinase-dead LIMK1 (LIMK1-KD), or of LIMK1 small interfering RNA, or of an activated cofilin mutant (cofilin S3A), selectively slowed down the exit from the trans-Golgi network (TGN) of the apical PM marker p75-green fluorescent protein (GFP) but did not interfere with the apical PM marker glycosyl phosphatidylinositol-YFP or the basolateral PM marker neural cell adhesion molecule-GFP. High-resolution live imaging experiments of carrier formation and release by the TGN and analysis of peri-Golgi actin dynamics using photoactivatable GFP suggest a scenario in which TGN-localized LIMK1-cofilin regulate a population of actin filaments required for dynamin-syndapin-cortactin-dependent generation and/or fission of precursors to p75 transporters.
Salvarezza
Susana B
SB
Margaret Dyson Vision Research Institute and Department of Cell and Developmental Biology, HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Medical College of Cornell University, New York, NY 10065, USA.
Deborde
Sylvie
S
Schreiner
Ryan
R
Campagne
Fabien
F
Kessels
Michael M
MM
Qualmann
Britta
B
Caceres
Alfredo
A
Kreitzer
Geri
G
Rodriguez-Boulan
Enrique
E
D051339:Actin Depolymerizing Factors / Q000235:genetics / Q000378:metabolism*; D000199:Actins / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002460:Cell Line; D016764:Cell Polarity; D003599:Cytoskeleton / Q000378:metabolism; D004285:Dogs; D034281:Dynamins / Q000235:genetics / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D054461:Lim Kinases / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D019006:Neural Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D020800:Receptor, Nerve Growth Factor / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism*
D051339:Actin Depolymerizing Factors; D000199:Actins; D015415:Biomarkers; D007527:Isoenzymes; D019006:Neural Cell Adhesion Molecules; D034741:RNA, Small Interfering; D020800:Receptor, Nerve Growth Factor; D011993:Recombinant Fusion Proteins; D054461:Lim Kinases; D034281:Dynamins