title: CrkL directs ASAP1 to peripheral focal adhesions.
abstract: Searching for proteins in platelets that can interact with the N-terminal SH3 domain of CrkL (using a combination of a pull-down assay followed by mass spectrometry), we have found that human platelets express an ADP-ribosylation factor (Arf)-specific GTPase-activating protein (GAP), ASAP1, as a CrkL-binding protein. In spreading platelets, most endogenous ASAP1 is localized at peripheral focal adhesions. To determine the physiologic significance of the CrkL-ASAP1 association, we overexpressed CrkL, ASAP1, or both in combination in COS7 cells. Unlike endogenous ASAP1 in platelets, overexpressed ASAP1 showed diffuse cytoplasmic distribution. However, when co-expressed with wild-type CrkL, both endogenous and expressed ASAP1 accumulated at CrkL-induced focal adhesions. An SH2-mutated CrkL, which cannot localize at focal adhesions, failed to recruit ASAP1 into focal adhesions. Thus, CrkL appears to be a lynchpin between ASAP1 and peripheral focal adhesions.
authors.affiliation: Laboratory of Environmental Biology, Department of Preventive Medicine, Hokkaido University School of Medicine, Sapporo 060-8638, Japan. aoda@med.hokudai.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Oda
authors.forename: Ikuo
authors.initials: I
authors.lastname: Wada
authors.forename: Koichi
authors.initials: K
authors.lastname: Miura
authors.forename: Katsuya
authors.initials: K
authors.lastname: Okawa
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Kadoya
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishihara
authors.forename: Masae
authors.initials: M
authors.lastname: Maeda
authors.forename: Shinya
authors.initials: S
authors.lastname: Tanaka
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagashima
authors.forename: Chiaki
authors.initials: C
authors.lastname: Nishitani
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Matsuno
authors.forename: Masaho
authors.initials: M
authors.lastname: Ishino
authors.forename: Laura M
authors.initials: LM
authors.lastname: Machesky
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Fujita
authors.forename: Paul
authors.initials: P
authors.lastname: Randazzo
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000097:blood*; D002448:Cell Adhesion / Q000502:physiology*; D002522:Chlorocebus aethiops; D022001:Focal Adhesions / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008024:Ligands; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000097:blood* / Q000737:chemistry; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D010973:Platelet Adhesiveness / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C082869:CRKL protein; D002352:Carrier Proteins; D008024:Ligands; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011994:Recombinant Proteins