9.B.26 The Regulator of ER Stress and Autophagy TMEM208 (TMEM208) Family

TMEM208 family proteins are small protein of about 175 aas and 4 TMSs that appear to play roles in ER stress and autophagy regulation (Zhao et al. 2013).  These proteins are constituents of the SRP-independent targeting (SND) Family (TC# 9.A.64) (Aviram et al. 2016). Understanding protein targeting to the endoplasmic reticulum (ER) was expanded by the discovery of multiple pathways that function in parallel to the signal recognition particle (SRP). Guided entry of tail-anchored proteins and SRP independent (SND) systems are two such targeting pathways described in yeast. hSnd2 is the first constituent of the human SND pathway able to support substrate-specific protein targeting to the ER. Similar to its yeast counterpart, hSnd2 is assumed to function as a membrane-bound receptor preferentially targeting precursors carrying C-terminal transmembrane domains. Thus, hSnd2 is part of a complex network of targeting and translocation that is dynamically regulated (Haßdenteufel et al. 2017). ER stress seems to play a role in differentiation of cells of mesenchymal origin (Turishcheva et al. 2022).  O-linked N-acetylglucosamine protein modification regulaties autophagy (Zhu et al. 2024).


 

References:

Aviram, N., T. Ast, E.A. Costa, E.C. Arakel, S.G. Chuartzman, C.H. Jan, S. Haßdenteufel, J. Dudek, M. Jung, S. Schorr, R. Zimmermann, B. Schwappach, J.S. Weissman, and M. Schuldiner. (2016). The SND proteins constitute an alternative targeting route to the endoplasmic reticulum. Nature 540: 134-138.

Haßdenteufel, S., M. Sicking, S. Schorr, N. Aviram, C. Fecher-Trost, M. Schuldiner, M. Jung, R. Zimmermann, and S. Lang. (2017). hSnd2 protein represents an alternative targeting factor to the endoplasmic reticulum in human cells. FEBS Lett. 591: 3211-3224.

Turishcheva, E., M. Vildanova, G. Onishchenko, and E. Smirnova. (2022). The Role of Endoplasmic Reticulum Stress in Differentiation of Cells of Mesenchymal Origin. Biochemistry (Mosc) 87: 916-931.

Zhao, Y., J. Hu, G. Miao, L. Qu, Z. Wang, G. Li, P. Lv, D. Ma, and Y. Chen. (2013). Transmembrane protein 208: a novel ER-localized protein that regulates autophagy and ER stress. PLoS One 8: e64228.

Zhu, Z., W. Ren, S. Li, L. Gao, and K. Zhi. (2024). Functional significance of O-linked N-acetylglucosamine protein modification in regulating autophagy. Pharmacol Res 202: 107120.

Examples:

TC#NameOrganismal TypeExample
9.B.26.1.1

The TMEM208 protein, involved in autophagy and ER stress regulation (Zhao et al. 2013).

Animals

TMEM208 of Homo sapiens

 
9.B.26.1.2

The DUF788 family protein of 4 TMSs in a 2 + 2 arrangement.

Slime molds

DUF788 protein of Dictyostelium purpureum

 
9.B.26.1.3

TMEM208 homologue of 180 aas and 3 or 4 TMSs.

Algae

TMEM208 homologue of Galdieria sulphuraria (Red alga)

 
9.B.26.1.4

Uncharacterized protein of 171 aas and 4 TMSs.

Fungi

UP of Penicillium digitatum (Green mold)

 
Examples:

TC#NameOrganismal TypeExample
9.B.26.2.1

Uncharacterized protein of 163 aas and 4 TMSs in a 2 + 2 TMS arrangement.

Ciliates

UP of Tetrahymena thermophila

 
9.B.26.2.2

Uncharacterized protein of 151 aas and 4 TMSs

Alveolata

UP of Plasmodium vivax

 
9.B.26.2.3

Uncharacterized protein of 141 aas and 4 TMSs

Parabasalia

UP of Trichomonas vaginalis