The European TRIM-NET network in drug discovery targeting TRIM Ubiquitin ligase is recruiting 12 PhD students (see attached file for details).
Applications before April 15th for a final selection on May 9th and 10th.
The positions are particularly interesting in terms of salary. More importantly, through a unique international partnership between academic and non-academic partners the TRIM-NET training programme will provide young researchers with skills required for biomedical research in industry and academia. The only requirement is that applicants must apply for an open position in a country different from the one where they have completed their studies in the last 12 months. It is strongly advised to contact the project managers before the selection.
For any information, contact Daniel Taillandier: firstname.lastname@example.org
Field of research
Proteolysis plays a key role in controlling muscle growth and atrophy. However, the regulatory mechanisms by which nutrients, hormones and/or physical activity control proteolysis are still poorly understood. Our works indicate that the Ubiquitin Proteasome System (UPS) is responsible for the breakdown of the major contractile proteins. The UPS is a highly complex and tightly regulated proteolytic system comprising hundreds of enzymes that plays a crucial role in controlling skeletal muscle mass. We study the precise mechanisms responsible for this adaptation in numerous catabolic situations (fasting, immobilization, cancer, sepsis, aging, …), and the potential coordination of this proteolytic machinery with other proteolytic systems (i.e. the lysosomal and caspase pathways). We are also seeking for biomarkers of muscle wasting, particularly during sarcopenia, which is the age-dependent loss of skeletal muscle. Ongoing projects include the following approaches: protein-protein interaction studies using yeast 2- and 3-hybrid screens and SPR (Biacore); transfection in various cellular (C2C12, L6, …) and animal (rodents) models; human catabolic situations (biopsies).
Understanding the regulatory mechanisms that control muscle mass is compulsory to ultimately preserve muscle strength during aging and many pathological wasting conditions like cancers, infections, trauma, renal failure, etc. Therefore, our final goal is to propose new therapeutic approaches that may prevent or limit muscle loss in catabolic conditions and/or improve muscle recovery following atrophying situations. These studies are of obvious clinical interest for reducing the length of hospitalizations and for improving treatments efficiency, and thus should ultimately result in decreased health care costs.
As a key player in muscle atrophy, the Ubiquitin Proteasome System (UPS) is a potential target for fighting against an exacerbated proteolysis. UPS substrates are labeled by a ubiquitin chain catalyzed by a coordinated enzymatic cascade E1-E2-E3. The polyubiquitinated proteins are then degraded by the 26S proteasome. The UPS regulates numerous cellular processes and the proteasome is common to all the proteins to be degraded. Thus, targeting the proteasome would inhibit the whole UPS-linked cellular protein degradation and would be highly toxic for cells. By contrast, E2-E3 couples (35 and > 600 respectively) are responsible for UPS selectivity, the E3 ligase being responsible for the recognition of the substrate while the E2 defines the type of ubiquitin chain linked to the substrate. Thus, E2-E3 couples represent a more promising target for fighting against muscle atrophy.
We demonstrated that α-actin is a UPS substrate in cultured myotubes and in human biopsies. In addition, the muscle-specific E3 ligase MuRF1 targets the myofibrillar actin pool (Polge et al, 2011). Thus, we aimed to identify the E2 enzymes that collaborate with MuRF1 during a catabolic situation. We screened for the E2 enzymes highly expressed in skeletal muscle and showed that one of them, UBE2B, was recruited upon mild atrophying conditions and was able to target the cytoplasmic pool of actin for MuRF1-independent degradation, which suggests that different E2-E3 couples target distinct pools of actin (Polge et al, 2015). Using complementary approaches, we recently identified E2 enzymes interacting with MuRF1 Polge et al., 2018). We are currently studying their capacity to target the main contractile proteins (actin, myosin heavy chains, …) both in vitro and in vivo.
Aniort J, Stella A, Philipponnet C, Poyet A, Polge C, Claustre A, Combaret L, Béchet D, Attaix D, Boisgard S, Filaire M, Rosset E, Burlet-Schiltz O, Heng AE, Taillandier D. Muscle wasting in patients with end-stage renal disease or early-stage lung cancer: common mechanisms at work. J Cachexia Sarcopenia Muscle. 2019 Jan 29. doi: 10.1002/jcsm.12376. PMID:30697967
Polge C, Cabantous S, Deval C, Claustre A, Hauvette A, Bouchenot C, Aniort J, Béchet D, Combaret L, Attaix D, Taillandier D. A muscle-specific MuRF1-E2 network requires stabilization of MuRF1-E2 complexes by telethonin, a newly identified substrate. J Cachexia Sarcopenia Muscle, 9:129-145. doi: 10.1002/jcsm.12249, 2018.
Polge C, Leulmi R, Jarzaguet M, Claustre A, Combaret L, Béchet D, Heng AE, Attaix D, Taillandier D. UBE2B is implicated in myofibrillar protein loss in catabolic C2C12 myotubes. J Cachexia Sarcopenia Muscle, 7:377-87. doi: 10.1002/jcsm.12060, 2016
Polge C, Attaix D, Taillandier D. Role of E2-Ub-conjugating enzymes during skeletal muscle atrophy. Front Physiol. 10, 6:59. doi: 10.3389/fphys.2015.00059, 2015
Attaix D, Taillandier D. The missing link: Mul1 signals mitophagy and muscle wasting. Cell Metabolism 16, 551-552, 2012
Polge C, Heng AE, Jarzaguet M, Ventadour S, Claustre A, Combaret L, Béchet D, Matondo M, Uttenweiler-Joseph S, Monsarrat B, Attaix D, Taillandier D. Muscle actin is polyubiquitinylated in vitro and in vivo and targeted for breakdown by the E3 ligase MuRF1. FASEB J., 25, 3790-802. 2011.
Heng A. E, Ventadour S., Jarzaguet M., Pouch-Pélissier M.N., Guezennec C. Y., Bigard X., Attaix D. and Taillandier D. Coordinate expression of the 19S regulatory complex and evidence for ubiquitin-dependent telethonin degradation in the unloaded soleus muscle. Int. J. Biochem. Cell. Biol.. 40, 2544–2552, 2008
- 1988: Appointed as an Engineer at the Laboratoire d'Etude du Métabolisme Azoté, INRA de Theix, France.
- 1991: Integrate the Proteolysis team
- 1993: Earned Ph.D.: « Regulation of skeletal muscle protein metabolism in hindlimb suspended rats”.
- 1996-1998: post-doctoral position in Pr. Martin Rechsteiner’s laboratory at the Biochemistry department - University of Utah (USA):
« Structure of the 19S regulatory complex of the 26S proteasome – role of individual subunits »
- 2000: Appointed as an Assistant Professor at the Nutrition and Protein Metabolism Unit, INRA de Theix, France.
- 2009: Associate Professor – « UPS substrates in atrophying skeletal muscles » “Habilitation à Diriger des Recherches” (Université d’Auvergne, Clermont-Fd I),
NATO Grant: post-doctoral fellowship (1996-1997).
INRA Grant: post-doctoral fellowship (1997-1998).
AFM-Téléthon Grant: « Degradation of the main skeletal muscle proteins (actin, myosin, …) », 2005-2007, 50 k€.
AFM-Téléthon Grant: « Metabolism of the major skeletal muscle proteins (actin, myosin, telethonin…): Identification of the E3 ligases involved », 2008-2011, 60 k€
INCa-DAAD Grant: (Germany-France collaboration), « p53 degradation by the 26S proteasome. Impact of Mdm2-mediated modifications of individual proteasomal subunits », 2008-2010, 25 k€.
Internal Grant: ANSSD du Département AlimH. « Rôle de la vitamine D sur l'inhibition de la synthèse protéique musculaire par le palmitate : recherche des mécanismes mis en jeu », 2012, 6 k€
AFM-Téléthon Grant: « Identification of E2/E3 couples involved in skeletal muscle atrophy », 2012-2014, 33 k€.
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