Rhophilin-2 is targeted to late-endosomal structures of the vesicular machinery in the presence of activated RhoB.
Rhophilin-2 or p76(RBE), a protein whose expression is induced by the cyclic AMP pathway in thyrocytes, contains several protein-protein interaction domains including HR-1, Bro1 and PDZ domains, and is a partner of RhoB in its GTP-bound form (Eur J Biochem, 269(24): 6241-9, 2002). We here define its subcellular localization and dissect the significance of its domains. By subcellular fractionation and colocalization experiments, rhophilin-2 is recruited to subcellular organelles by activated RhoB-GTP. As for its yeast homologue, Npi3/Bro1p, the Bro1 domain of rhophilin-2 is necessary to its recruitment to the vesicular structures, which are not labeled for EEA1 nor Lamp1, but well with the late endosome marker CD63.
Steuve
Séverine
S
Free University of Brussels-Campus Erasme, Institute of Interdisciplinary Research, 808 route de Lennik-1070 Brussels, Belgium. ssteuve@ulb.ac.be
Devosse
Thalie
T
Lauwers
Elsa
E
Vanderwinden
Jean-Marie
JM
André
Bruno
B
Courtoy
Pierre J
PJ
Pirson
Isabelle
I
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D004285:Dogs; D056827:Endosomal Sorting Complexes Required for Transport; D011992:Endosomes / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology; D013347:Subcellular Fractions / Q000378:metabolism*; D014162:Transfection; D022161:Transport Vesicles / Q000201:enzymology / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000502:physiology; D020743:rhoB GTP-Binding Protein / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C480237:Bro1 protein, S cerevisiae; D056827:Endosomal Sorting Complexes Required for Transport; C471419:RHPN2 protein, human; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D020743:rhoB GTP-Binding Protein