Three modules of zebrafish Mind bomb work cooperatively to promote Delta ubiquitination and endocytosis.
Precise regulation of Notch signaling activity is critical for development of many different tissues. Here, we show that the zebrafish insertional mutation Hi904 attenuates Notch signaling, and is allelic to mind bomb. We show that Mind bomb protein displays E3 ubiquitin ligase activity in vitro and that it is associated with Delta and enhances its ubiquitination and internalization in transfected cells. Furthermore, by functional analysis of three conserved regions of Mind bomb, we show that the N-terminal half is required for Delta association, the ankyrin repeats are important for Delta internalization, and the ring fingers are required for Delta ubiquitination. Thus, the three functionally distinct modules of Mind bomb work cooperatively to regulate Notch signaling by associating with, ubiquitinating, and internalizing Delta.
Chen
Wenbiao
W
Vollum Institute, Oregon Health and Science University, Portland, OR 97201, USA. chenwb@ohsu.edu
Casey Corliss
D
D
D000595:Amino Acid Sequence; D000818:Animals; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D004705:Endocytosis; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010957:Plasmids; D011233:Precipitin Tests; D051880:Receptors, Notch; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D014452:Ubiquitins / Q000378:metabolism*; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D018076:DNA, Complementary; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051880:Receptors, Notch; D014452:Ubiquitins; D029961:Zebrafish Proteins; C064045:delta protein; D044767:Ubiquitin-Protein Ligases; C471932:mib1 protein, zebrafish