TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
8.A.74.1.1









Integrin β-like protein A of 1927 aas and 2 TMSs, N- and C-terminal, Sib1 of the TM9 (Phg1) family. Serves as an intramembrane cargo receptor controlling exocytosis and surface localization of a subset of membrane proteins (Perrin et al. 2015).

Eukaryota
Dictyosteliida
Sib1 of Dictyostelium discoideum (Slime mold)
8.A.74.1.2









Neurexin-1 (NRX1) of 1477 aas and 2 TMSs, one N-terminal and one C-terminal.  It is a cell surface protein involved in cell-cell-interactions, exocytosis of secretory granules and regulation of signal transmission including several transport systems. Neurexin function is isoform-specific. It is found in trans-synaptic tripartite complexes which consist of one unit of the cerebellin-1 (Cbln1) hexamer,  four monomeric neurexins containing a splice site 4 insertion at presynaptic terminals and the postsynaptic GluD2 dimers (Matsuda 2016). The trans-synaptic interaction of postsynaptic glutamate receptor δ2 (GluRδ2, an orthologue of TC#1.A.10.1.8) and presynaptic neurexins through cerebellin precursor protein 1 (Cbln1) mediates synapse formation in vivo in the cerebellum (Lee et al. 2012). Members of the neurexin family appear to be homologous to domains in some members of TC family 9.B.87.

Eukaryota
Metazoa
Neurexin-1 of Homo sapiens
8.A.74.1.3









Agrin (GRN) of 2068 aas and 1 or 2 TMSs, is a heparan sulfate basal lamina glycoprotein that plays a central role in the formation and the maintenance of neuromuscular junctions (NMJs) and directs key events in postsynaptic differentiation. It is a component of the AGRN-LRP4 receptor complex that induces the phosphorylation and activation of MUSK. The activation of MUSK in myotubes induces the formation of NMJs by regulating different processes including the transcription of specific genes and the clustering of AChR in the postsynaptic membrane, the latter which requires calcium ions for clustering (Huzé et al. 2009; Zhang et al. 2011). Agrin, Lrp4, and MuSK, are required for the initial formation, subsequent maturation, and long-term stabilization of mammalian neuromuscular synapses (Koppel et al. 2019). It maky play a role in frontotemporal dementia (FTD) (Lok and Kwok 2021).

Eukaryota
Metazoa
Agrin of Homo sapiens
8.A.74.1.4









Tomoregulin-1 or transmembrane protein with EGF-like and two follistatin-like domains 1 (TMEFF1) of 270 aas and 2 TMSs, one N-terminal and the other C-terminal. It may inhibit NODAL and BMP signaling during neural patterning, and may also be a tumor suppressor in brain cancers (Gery et al. 2003). It may modulate ion channel transport and glucose metabolism (Hudlikar et al. 2021).

Eukaryota
Opisthokonta
TMEFF1 of Homo sapiens
8.A.74.1.5









Hevin or Sparc-like protein 1, SPARCL1, also called Proliferation-inducing protein, PIG33, of 664 aas and one N-terminal TMS. It regulates Insulin-like Growth Factor (IGF) transport and uptake by Insulin-like Growth Factor Binding Proteins (IGFBPs). It is a matricellular protein involved in tissue repair and remodeling, and is crucial for initiation and development of excitatory synapses. Specifically, it is important for AMPA receptor and its meditation of fast synaptic transmission in the central nervous system (CNS) (Wang et al. 2020). Thus, spinal Hevin is involved in the maintenance of remifentanil-induced postoperative hyperalgesia via modulating membrane trafficking of AMPA receptors (Wang et al. 2020).

Eukaryota
Opisthokonta
Hevin of Homo sapiens