title: Invertebrate and vertebrate class III myosins interact with MORN repeat-containing adaptor proteins.
abstract: In Drosophila photoreceptors, the NINAC-encoded myosin III is found in a complex with a small, MORN-repeat containing, protein Retinophilin (RTP). Expression of these two proteins in other cell types showed NINAC myosin III behavior is altered by RTP. NINAC deletion constructs were used to map the RTP binding site within the proximal tail domain of NINAC. In vertebrates, the RTP ortholog is MORN4. Co-precipitation experiments demonstrated that human MORN4 binds to human myosin IIIA (MYO3A). In COS7 cells, MORN4 and MYO3A, but not MORN4 and MYO3B, co-localize to actin rich filopodia extensions. Deletion analysis mapped the MORN4 binding to the proximal region of the MYO3A tail domain. MYO3A dependent MORN4 tip localization suggests that MYO3A functions as a motor that transports MORN4 to the filopodia tips and MORN4 may enhance MYO3A tip localization by tethering it to the plasma membrane at the protrusion tips. These results establish conserved features of the RTP/MORN4 family: they bind within the tail domain of myosin IIIs to control their behavior.
authors.affiliation: Department of Biology, Indiana University South Bend, South Bend, Indiana, United States of America.
authors.forename: Kirk L
authors.initials: KL
authors.lastname: Mecklenburg
authors.affiliation: Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Freed
authors.affiliation: Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, United States of America.
authors.forename: Manmeet
authors.initials: M
authors.lastname: Raval
authors.affiliation: Department of Biology, University of Richmond, Richmond, Virginia, United States of America.
authors.forename: Omar A
authors.initials: OA
authors.lastname: Quintero
authors.affiliation: Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, United States of America.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Yengo
authors.affiliation: Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: O'Tousa
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D004330:Drosophila / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism; D007448:Invertebrates / Q000378:metabolism*; D025102:Myosin Type III / Q000378:metabolism*; D010786:Photoreceptor Cells / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary; D011554:Pseudopodia / Q000378:metabolism; D014714:Vertebrates / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D029721:Drosophila Proteins; D005136:Eye Proteins; C520357:rtp protein, Drosophila; D025102:Myosin Type III
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