8.A.146. The Nodal Modulator (NOMO) Family McGilvray et al. 2020 described a ~ 360 kDa ribosome-associated complex comprising the core Sec61 channel (TC# 3.A.5.9.1) and five accessory factors: TMCO1 (TC# 1.A.106.1.1), CCDC47 (TC# 8.A.142.1.1) and the Nicalin (TC# 8.A.144.1.1)-TMEM147 (TC# 8.A.145.1.1)-NOMO 2 (TC# 8.A.146.1.1) complex. Cryo-EM revealed a large assembly at the ribosome exit tunnel organized around a central membrane cavity. Similar to protein-conducting channels that facilitate movement of TMSs, cytosolic and luminal funnels in TMCO1 and TMEM147, respectively, suggested routes into the central membrane cavity. High-throughput mRNA sequencing showed selective translocon engagement with hundreds of different multi-pass membrane proteins. Consistent with a role in multi-pass membrane protein biogenesis, cells lacking different accessory components of this complex showed reduced levels of one such client, the glutamate transporter EAAT1 (TC# 2.A.23.2.6). These findings identified a human translocon and provided a molecular framework for understanding its role in multi-pass membrane protein biogenesis (McGilvray et al. 2020).
References:
McGilvray, P.T., S.A. Anghel, A. Sundaram, F. Zhong, M.J. Trnka, J.R. Fuller, H. Hu, A.L. Burlingame, and R.J. Keenan. (2020). An ER translocon for multi-pass membrane protein biogenesis. Elife 9:.
Examples:
TC#	Name	Organismal Type	Example
8.A.146.1.1	The nodal modulator 2, NOMO2, protein of 1,267 aas and 1 N-terminal TMS, and possibly another near the C-terminus. This protein forms a complex with Sec61 (3.A.5.9.1) and other accessory proteins (McGilvray et al. 2020).		NOMO2 of Homo sapiens

8.A.146.1.2	Uncharacterized protein of 1338 aas and several hydrophobic peaks that may be TMSs.		UP of Sparganum proliferum

Examples:
TC#	Name	Organismal Type	Example
8.A.146.2.1	LPXTG cell wall anchor domain-containing protein of 1529 aas and 2 TMSs, N- and C-terminal.		Cell wall anchor domain protein of Listeria monocytogenes

8.A.146.2.2	LPXTG cell wall anchor domain-containing protein of 3236 aas and 2 TMSs, one N-terminal and the other C-terminal.		Cell wall anchor protein of Bacillus thuringiensis

Examples:
TC#	Name	Organismal Type	Example
8.A.146.3.1	Carboxypeptidase regulatory-like domain-containing protein of 677 aas and 1 N-terminal TMS.		Carboxypeptidase regulatory protein of Steroidobacter agariperforans

8.A.146.3.2	Uncharacterized putative lipoprotein of 936 aas and 1 N-terminal TMS.		UP of Corallococcus macrosporus

8.A.146.3.3	Uncharacterized protein of 2544 aas and 3 TMSs, one at the N-terminus and two at the C-terminus.		UP of Corynebacterium gottingense