title: Rapid trafficking of c-Src, a non-palmitoylated Src-family kinase, between the plasma membrane and late endosomes/lysosomes.
abstract: Src-family kinases (SFKs) are co-expressed with multiple combinations of each member in a single cell and involved in various signalings. Recently, we showed by sucrose-density gradient fractionation that the subcellular distribution of c-Src is distinct from that of Lyn. However, little is known about the trafficking of c-Src in living cells. Here, we show by time-lapse monitoring combined with photobleaching techniques that c-Src, a non-palmitoylated SFK, is rapidly exchanged between the plasma membrane and intracellular organelles representing late endosomes/lysosomes possibly through its cytosolic release. Although Lyn, a palmitoylated SFK, is exocytosed to the plasma membrane via the Golgi apparatus along the secretory pathway, lack of palmitoylation directs Lyn away from the exocytotic transport to the c-Src-type trafficking between the plasma membrane and late endosomes/lysosomes. Intriguingly, c-Src and a non-palmitoylated Lyn mutant are efficiently delivered and immobilized to focal adhesions when their SH2 domains are able to mediate protein-protein interactions in place of intramolecular bindings. However, palmitoylation of Lyn inhibits its recruitment to focal adhesions. These results suggest that palmitoylation of SFKs is critical for SFK localization and trafficking and implicate that two distinct trafficking pathways for SFKs may be involved in SFKs' specific functions.
authors.affiliation: Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan.
authors.forename: Kousuke
authors.initials: K
authors.lastname: Kasahara
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Akio
authors.initials: A
authors.lastname: Kihara
authors.forename: Daisuke
authors.initials: D
authors.lastname: Matsuda
authors.forename: Kikuko
authors.initials: K
authors.lastname: Ikeda
authors.forename: Takahisa
authors.initials: T
authors.lastname: Kuga
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Fukumoto
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Naoto
authors.initials: N
authors.lastname: Yamaguchi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism*; D002470:Cell Survival; D002522:Chlorocebus aethiops; D004285:Dogs; D011992:Endosomes / Q000378:metabolism*; D022001:Focal Adhesions / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D008969:Molecular Sequence Data; D019308:Palmitic Acid / Q000378:metabolism; D021381:Protein Transport; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D018909:src Homology Domains; D019061:src-Family Kinases / Q000737:chemistry
chemical_list: D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D019308:Palmitic Acid; D016392:Proto-Oncogene Proteins pp60(c-src); C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases