beta III Spectrin Regulates the Structural Integrity and the Secretory Protein Transport of the Golgi Complex
Por:
Salcedo-Sicilia, L, Granell, S, Jovic, M, Sicart, A, Mato, E, Johannes, L, Balla, T, Egea, G
Publicada:
25 ene 2013
Resumen:
A spectrin-based cytoskeleton is associated with endomembranes, including the Golgi complex and cytoplasmic vesicles, but its role remains poorly understood. Using new generated antibodies to specific peptide sequences of the human beta III spectrin, we here show its distribution in the Golgi complex, where it is enriched in the trans-Golgi and trans-Golgi network. The use of a drug-inducible enzymatic assay that depletes the Golgi-associated pool of PI4P as well as the expression of PH domains of Golgi proteins that specifically recognize this phosphoinositide both displaced beta III spectrin from the Golgi. However, the interference with actin dynamics using actin toxins did not affect the localization of beta III spectrin to Golgi membranes. Depletion of beta III spectrin using siRNA technology and the microinjection of anti-beta III spectrin antibodies into the cytoplasm lead to the fragmentation of the Golgi. At ultrastructural level, Golgi fragments showed swollen distal Golgi cisternae and vesicular structures. Using a variety of protein transport assays, we show that the endoplasmic reticulum-to-Golgi and post-Golgi protein transports were impaired in beta III spectrin-depleted cells. However, the internalization of the Shiga toxin subunit B to the endoplasmic reticulum was unaffected. We state that beta III spectrin constitutes a major skeletal component of distal Golgi compartments, where it is necessary to maintain its structural integrity and secretory activity, and unlike actin, PI4P appears to be highly relevant for the association of beta III spectrin the Golgi complex.
Filiaciones:
Salcedo-Sicilia, L:
Univ Barcelona, Fac Med, Dept Biol Cel Lular Immunol & Neurociencies, Barcelona 08036, Spain
Granell, S:
Univ Barcelona, Fac Med, Dept Biol Cel Lular Immunol & Neurociencies, Barcelona 08036, Spain
Jovic, M:
NICHD, Sect Mol Signal Transduct, Program Dev Neurosci, NIH, Bethesda, MD USA
Sicart, A:
Univ Barcelona, Fac Med, Dept Biol Cel Lular Immunol & Neurociencies, Barcelona 08036, Spain
Mato, E:
Univ Barcelona, Fac Med, Dept Biol Cel Lular Immunol & Neurociencies, Barcelona 08036, Spain
Hosp Santa Creu & Sant Pau, Ctr Invest Biomed Red Bioingn Biomat & Nanomed, Barcelona 08025, Spain
Johannes, L:
Inst Curie, Ctr Rech, Traff Signaling & Delivery Grp, F-75005 Paris, France
CNRS, UMR144, F-75700 Paris, France
Balla, T:
NICHD, Sect Mol Signal Transduct, Program Dev Neurosci, NIH, Bethesda, MD USA
Egea, G:
Univ Barcelona, Fac Med, Dept Biol Cel Lular Immunol & Neurociencies, Barcelona 08036, Spain
Inst Invest Biomed August Pi & Sunyer Nanociencia, Barcelona 08036, Spain
Hybrid Gold, Green Published
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