Exosome secretion, including the DNA damage-induced p53-dependent secretory pathway, is severely compromised in TSAP6/Steap3-null mice

Abstract

TSAP6 (tumor suppressor-activated pathway 6), also known as Steap3, is a direct p53 transcriptional target gene. It regulates protein secretion, for example translationally controlled tumor protein (TCTP), which is implicated in tumor reversion. In keeping with the latter, we show herein that TSAP6 is a glycosylated protein present in the trans-Golgi network, endosomal-vesicular compartment and cytoplasmic membrane. To further investigate the physiological function of TSAP6, we have generated TSAP6-deficient mice. These mice exhibit microcytic anemia with abnormal reticulocyte maturation and deficient transferrin receptor downregulation, a process known to be dependent on exosomal secretion. Moreover, we provide direct evidence that exosome production is severely compromised in TSAP6-null cells. Finally, we show that the DNA damage-induced p53-dependent nonclassical exosomal secretory pathway is abrogated in TSAP6-null cells. Given the fact that exosomes are used as cell-free vaccines against cancer and that they could be involved in the biogenesis and spread of human immunodeficiency virus, it is important to understand their regulation. The results presented here provide the first genetic demonstration that exosome formation is a tightly controlled biological process dependent of TSAP6.

Engineering mesenchymal stem cells to improve their exosome efficacy and yield for cell‐free therapy

“…There are also multipass membrane proteins that could regulate the exosome release such as the tumour suppressor activated pathway-6 (TSAP6), which is a p53 -inducible gene. This was confirmed when TSAP6-null mice showed a severe compromised exosome secretion and their p53-dependent secretory pathway abrogated [62,63]. This pathway is also a substrate of a protein that provides negative feedback to exosome secretion, rhomboid domain containing 1 (RHBDD1) protein [64].…”

Exosomes as intercellular signalosomes and pharmacological effectors

“…Exosomes production appears as a tightly controlled biological process dependent upon p53 regulated transcription genes such as the Tumor Supression Activated Pathway 6 (TSAP6) [44]. Thus, TSAP6 has been shown to increase the exosome secretion following stress events such as those inducing DNA damage (senescence, radiations ...) [44].…”

“…Thus, TSAP6 has been shown to increase the exosome secretion following stress events such as those inducing DNA damage (senescence, radiations ...) [44].…”

Silencing of human papillomavirus (HPV) E6/E7 oncogene expression affects both the contents and the amounts of extracellular microvesicles released from HPV‐positive cancer cells

“…Cell pellets were lysed in RIPA buffer [10 mM Tris, pH 7.5, 150 mM NaCl, 1 mM EDTA, 1% Nonidet P 40 , 0.5% NaDeoxycholat, 0.1% SDS, supplemented with 25 ml/ml Pefabloc (Merck, Whitehouse Station, NJ) and 10 ml/ml of Protease Inhibitor Cocktail (Sigma-Aldrich)] for 30 min on ice, and then the proteins were collected by centrifugation at 12,000g for 15 min. Protein concentrations were determined by the Bio-Rad Protein Assay (Bio-Rad, Hercules, CA) using bovine serum albumin as standard.…”