CIN85 associates with multiple effectors controlling intracellular trafficking of epidermal growth factor receptors.
CIN85 is a multidomain adaptor protein involved in Cbl-mediated down-regulation of epidermal growth factor (EGF) receptors. CIN85 src homology 3 domains specifically bind to a proline-arginine (PxxxPR) motif in Cbl, and this association seems to be important for EGF receptor endocytosis. Here, we report identification of novel CIN85 effectors, all containing one or more PxxxPR motifs, that are indispensable for their mutual interactions. These effectors include phosphatidyl-inositol phosphatases SHIP-1 and synaptojanin 2B1, Arf GTPase-activating proteins ASAP1 and ARAP3, adaptor proteins Hip1R and STAP1, and a Rho exchange factor, p115Rho GEF. Acting as a molecular scaffold, CIN85 clusters its effectors and recruits them to high-molecular-weight complexes in cytosolic extracts of cells. Further characterization of CIN85 binding to ASAP1 revealed that formation of the complex is independent on cell stimulation. Overexpression of ASAP1 increased EGF receptor recycling, whereas ASAP1 containing mutated PxxxPR motif failed to promote this event. We propose that CIN85 functions as a scaffold molecule that binds to numerous endocytic accessory proteins, thus controlling distinct steps in trafficking of EGF receptors along the endocytic and recycling pathways.
Kowanetz
Katarzyna
K
Institute of Biochemistry II, Goethe University Medical School, 60590 Frankfurt, Germany.
Husnjak
Koraljka
K
Höller
Daniela
D
Kowanetz
Marcin
M
Soubeyran
Philippe
P
Hirsch
Dianne
D
Schmidt
Mirko H H
MHH
Pavelic
Kresimir
K
De Camilli
Pietro
P
Randazzo
Paul A
PA
Dikic
Ivan
I
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D020816:Amino Acid Motifs; D001665:Binding Sites; D002460:Cell Line; D066246:ErbB Receptors / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D006801:Humans; D042541:Intracellular Space / Q000648:ultrastructure; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D011990:Receptors, Transferrin / Q000235:genetics; D014168:Transferrin / Q000032:analysis
C446512:ARAP3 protein, human; C117891:ASAP1 protein, human; D048868:Adaptor Proteins, Signal Transducing; D020690:GTPase-Activating Proteins; D011990:Receptors, Transferrin; C433810:SH3KBP1 protein, human; D014168:Transferrin; D066246:ErbB Receptors