Plays a role during embryonic arterial endothelium differentiation and vascular morphogenesis through the ACVRL1 receptor-dependent signaling pathway upon stimulation by bone morphogenetic proteins, such as GDF2/BMP9 and BMP10 (PubMed:22783020). Involved in the regulation of nociception, acting as a modulator of the interaction between TRPA1 and TRPV1, two molecular sensors and mediators of pain signals in dorsal root ganglia (DRG) neurons (PubMed:25640077). Mechanistically, it weakens their interaction, thereby releasing the inhibition of TRPA1 by TRPV1 and increasing the single-channel open probability of the TRPA1-TRPV1 complex (PubMed:25640077). Interacts (via C-terminus) with TRPA1 and TRPV1 (PubMed:25640077). Interacts with TASOR (PubMed:31112734). Colocalized with HSPA5 in the endoplasmic reticulum (ER). Enriched in ER microsome. Colocalized with BMP4 in neural cell bodies and neural fibers of the enteric nervous system (By similarity). Expressed in dorsal root ganglia. Expressed in neurons as well as nerve fiber bundles connecting ganglia and fibers innervating muscle layer of the gastric body, jejunum, and proximal colon. Expressed in arterial endothelial cells and neurons of the central nervous system and peripheral nervous system (at protein level). Expressed strongly in lung, weakly in brain, heart and muscle. Expressed in enteric neurons and vascular tissue in the muscularis propria of the gastrointestinal tract. Expressed in embryo at 8.5 dpc. Expressed in arterial endothelial cells of the pharyngeal arch artery and endocardium at 9.5 dpc, onward. Expressed in dorsal aorta, pharyngeal arch and primitive internal carotid arteries at 11.5 dpc. Expressed also in intersomitic, mesenchephalic, metencephalic and anterior choroidal arteries at 12.5 dpc. Expressed in the ventral neural tube of the embryo. Mice die at a mid- or late-gestational period. Show embryonic lethality due to impaired differentiation of arterial endothelium and defects of vascular morphogenesis (PubMed:22783020). Conditional knockout in endothelial cells show similar vascular defects to those observed in global null mice (PubMed:20848592, PubMed:22783020). Conditional knockout mice lacking Tmem100 in dorsal root ganglia (DRG) primary sensory neurons, exhibit normal mechanical sensitivity but reduced acute nocifensive behaviors induced by mustard oil, consistent with a reduction in inflammatory mechanical hyperalgesia and TRPA1- but not TRPV1-mediated pain (PubMed:25640077).