RESUMO
Clathrin adaptor protein complex-1 (AP-1) and its accessory proteins play a role in the sorting of integral membrane proteins at the trans-Golgi network and endosomes. Their physiological functions in complex organisms, however, are not fully understood. In this study, we found that CG8538p, an uncharacterized Drosophila protein, shares significant structural and functional characteristics with Aftiphilin, a mammalian AP-1 accessory protein. The Drosophila Aftiphilin was shown to interact directly with the ear domain of γ-adaptin of Drosophila AP-1, but not with the GAE domain of Drosophila GGA. In S2 cells, Drosophila Aftiphilin and AP-1 formed a complex and colocalized at the Golgi compartment. Moreover, tissue-specific depletion of AP-1 or Aftiphilin in the developing eyes resulted in a disordered alignment of photoreceptor neurons in larval stage and roughened eyes with aberrant ommatidia in adult flies. Furthermore, AP-1-depleted photoreceptor neurons showed an intracellular accumulation of a Notch regulator, Scabrous, and downregulation of Notch by promoting its degradation in the lysosomes. These results suggest that AP-1 and Aftiphilin are cooperatively involved in the intracellular trafficking of Notch during eye development in Drosophila.
Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Olho/crescimento & desenvolvimento , Olho/metabolismo , Receptores Notch/metabolismo , Fator de Transcrição AP-1/metabolismo , Subunidades gama do Complexo de Proteínas Adaptadoras/química , Subunidades gama do Complexo de Proteínas Adaptadoras/genética , Subunidades gama do Complexo de Proteínas Adaptadoras/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Compartimento Celular , Linhagem Celular , Proteínas de Drosophila/química , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Endossomos/metabolismo , Anormalidades do Olho/genética , Anormalidades do Olho/metabolismo , Técnicas de Silenciamento de Genes , Glicoproteínas/metabolismo , Humanos , Lisossomos/metabolismo , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Células Fotorreceptoras de Invertebrados/citologia , Células Fotorreceptoras de Invertebrados/metabolismo , Domínios e Motivos de Interação entre Proteínas , Transporte Proteico , Interferência de RNA , Receptores Notch/genética , Homologia de Sequência de Aminoácidos , Transdução de Sinais , Fator de Transcrição AP-1/química , Fator de Transcrição AP-2/química , Fator de Transcrição AP-2/metabolismo , Rede trans-Golgi/metabolismoRESUMO
BACKGROUND: This study aimed to assess the deformation of the mitral valve complex during the displacement of the beating heart by using three-dimensional echocardiography in a porcine off-pump coronary artery bypass grafting (OPCAB) model. METHODS: In nine healthy swine, we positioned the beating heart as an OPCAB model, i.e. control, left anterior descending artery (LAD), right coronary artery (RCA), and left circumflex artery (LCX) positions. In each position, three-dimensional echocardiography was performed to assess the mitral valve complex with hemodynamic parameters. We analyzed the deformation of the mitral valve and the three-dimensional coordinates of the papillary muscles. RESULTS: There was a significant increase in maximum tenting length and tenting volume (control 0.70±0.30, LAD 0.65±0.27, RCA 0.79±0.23, LCX 0.95±0.34cm3, p<0.05) in the LCX position compared with the other positions. The posterior papillary muscle (PPM) angle had a significant relationship with the tenting volume (r=-0.643, p<0.001). The PPM was displaced to the medial side in the LAD and LCX positions (p<0.01). CONCLUSIONS: The prime cause of the deformation of the mitral leaflets is suggested to be the displacement of the PPM associated with the change in geometry of the left ventricle in a porcine model.