Endosomal proteolysis of internalized proteins

FEBS Letters

Bergeron, John J.M.²  Authier, François³  Posner, Barry I.¹ 

[1]DApartment of Medicine, McGill University, Montreal, Quebec H3A 2B2, Canada

[2]DApartment of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 2B2, Canada

[3]Institut National De la Santé et De la Recherche Médicale U30, Hôpital Necker Des Enfants Malades, 149 rue De Sèvres, 75015 Paris, France

关键词: Endosomes;    Endocytosis;    Major histocompatibility complex class II;    Antigen processing;    Endopeptidase;    Cathepsin;    EAI;    endosomal acidic insulinase;    ER;    endoplasmic reticulum;    Ii;    invariant chain;    MHC;    major histocompatibility complex;    EGF;    epidermal growth factor;    PTH;    parathyroid hormone;    HPLC;    high performance liquid chromatography;    TCA;    trichloroacetic acid;   

DOI  :  10.1016/0014-5793(96)00368-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Endosomal proteases have been implicated in the DAgradation of internalized regulatory peptides involved in the control of metabolic pathways and in the processing of intracellular antigens for cytolytic immune responses. Processing in the endocytic vesicles is regulated by changes in endosomal acidity due to the presence of an ATP-DApenDAnt proton pump which modulates protease activity, protein unfolding and receptor-ligand interactions. A limited number of proteases appear to reside in endosomes which do not contain the full complement of active proteases capable of completely DAgrading all internalized polypeptides. Retention of some acid hydrolases in endosomes is apparently related to their association with unDAfined endosomal membrane receptors. The limited number of proteases and the pH gradient from neutral to acidic (pH 7 to 5) within endosomes make possible a selective and controlled processing environment in comparison to lysosomes. The full set of endo- and exopeptidases that break down proteins to amino acids are active later in the pathway in lysosomes.

【 授权许可】

Unknown