title: MUC1 initiates Src-CrkL-Rac1/Cdc42-mediated actin cytoskeletal protrusive motility after ligating intercellular adhesion molecule-1.
abstract: MUC1, a transmembrane glycoprotein of the mucin family, when aberrantly expressed on breast cancer cells is correlated with increased lymph node metastases. We have previously shown that MUC1 binds intercellular adhesion molecule-1 (ICAM-1) on surrounding accessory cells and facilitates transendothelial migration of MUC1-bearing cells. Nevertheless, the underlying molecular mechanism is still obscure. In the present study, we used a novel assay of actin cytoskeletal reorganization to show that by ligating ICAM-1, MUC1 triggers Rac1- and Cdc42-dependent actin cytoskeletal protrusive activity preferentially at the heterotypic cell-cell contact sites. Further, we show that these MUC1/ICAM-1 interaction-initiated lamellipodial and filopodial protrusions require Src family kinase and CT10 regulator of kinase like (CrkL) accompanied by the rapid formation of a Src-CrkL signaling complex at the MUC1 cytoplasmic domain. Through inhibition of Src kinase activity, we further revealed that Src is required for recruiting CrkL to the MUC1 cytoplasmic domain as well as mediating the observed actin cytoskeleton dynamics. These findings suggest a novel MUC1-Src-CrkL-Rac1/Cdc42 signaling cascade following ICAM-1 ligation, through which MUC1 regulates cytoskeletal reorganization and directed cell motility during cell migration.
authors.affiliation: Department of Laboratory Medicine and Pathology, 5B4.21 Mackenzie Health Sciences Centre, University of Alberta Hospital, Edmonton, AB, Canada T6G 2R7.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shen
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Rahn
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Nirosha
authors.initials: N
authors.lastname: Gunasekera
authors.forename: Xuejun
authors.initials: X
authors.lastname: Sun
authors.forename: Andrew R E
authors.initials: AR
authors.lastname: Shaw
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hendzel
authors.forename: Pat
authors.initials: P
authors.lastname: Hoffman
authors.forename: Ashlyn
authors.initials: A
authors.lastname: Bernier
authors.forename: Judith C
authors.initials: JC
authors.lastname: Hugh
mesh_terms: D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement; D003599:Cytoskeleton / Q000201:enzymology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D051379:Mice; D018396:Mucin-1 / Q000378:metabolism*; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; C082869:CRKL protein; D018396:Mucin-1; D009687:Nuclear Proteins; D018799:Intercellular Adhesion Molecule-1; D016392:Proto-Oncogene Proteins pp60(c-src); D019061:src-Family Kinases; D010738:Type C Phospholipases; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein