Identification of mRNA/protein (mRNP) complexes containing Puralpha, mStaufen, fragile X protein, and myosin Va and their association with rough endoplasmic reticulum equipped with a kinesin motor.
Puralpha, which is involved in diverse aspects of cellular functions, is strongly expressed in neuronal cytoplasm. Previously, we have reported that this protein controls BC1 RNA expression and its subsequent distribution within dendrites and that Puralpha is associated with polyribosomes. Here, we report that, following treatment with EDTA, Puralpha was released from polyribosomes in mRNA/protein complexes (mRNPs), which also contained mStaufen, Fragile X Mental Retardation Protein (FMRP), myosin Va, and other proteins with unknown functions. As the coimmunoprecipitation of these proteins by an anti-Puralpha antibody was abolished by RNase treatment, Puralpha may assist mRNP assembly in an RNA-dependent manner and be involved in targeting mRNPs to polyribosomes in cooperation with other RNA-binding proteins. The immunoprecipitation of mStaufen- and FMRP-containing mRNPs provided additional evidence that the anti-Puralpha detected structurally or functionally related mRNA subsets, which are distributed in the somatodendritic compartment. Furthermore, mRNPs appear to reside on rough endoplasmic reticulum equipped with a kinesin motor. Based on our present findings, we propose that this rough endoplasmic reticulum structure may form the molecular machinery that mediates and regulates multistep transport of polyribosomes along microtubules and actin filaments, as well as localized translation in the somatodendritic compartment.
Ohashi
Sachiyo
S
Division of Biochemistry, College of Pharmacy, Nihon University, Chiba 274-8555, Japan.
Koike
Katsuya
K
Omori
Akira
A
Ichinose
Sachiyo
S
Ohara
Susumu
S
Kobayashi
Shunsuke
S
Sato
Taka-Aki
TA
Anzai
Kaijiro
K
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D015153:Blotting, Western; D001921:Brain / Q000502:physiology; D002499:Centrifugation, Density Gradient; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018870:Endoplasmic Reticulum, Rough / Q000502:physiology*; D016547:Kinesins / Q000502:physiology*; D051379:Mice; D018995:Myosin Heavy Chains / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D024701:Myosin Type V / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000502:physiology; D011132:Polyribosomes / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits; D018160:Receptors, Cytoplasmic and Nuclear; D012261:Ribonucleoproteins / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000099150:Receptor, Farnesoid X-Activated
D000906:Antibodies; D017362:Cyclic AMP Response Element-Binding Protein; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D016547:Kinesins; D018995:Myosin Heavy Chains; D024701:Myosin Type V; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D012261:Ribonucleoproteins; D014157:Transcription Factors; D000099150:Receptor, Farnesoid X-Activated; C513082:Myo5a protein, mouse; C121485:Pura protein, mouse; C492185:STAU1 protein, human; C492187:Stau1 protein, mouse; C026452:messenger ribonucleoprotein; C117884:staufen protein, mammalian