Involved in Golgi-to-endoplasmic reticulum (ER) retrograde transport; the function is proposed to depend on its association in the NRZ complex which is believed to play a role in SNARE assembly at the ER (PubMed:19369418). Required for normal embryonic development (By similarity). May play a role in the nonsense-mediated decay pathway of mRNAs containing premature stop codons (By similarity). Component of the NRZ complex composed of NBAS, ZW10 and RINT1/TIP20L; NRZ associates with SNAREs STX18, USE1, BNIP1/SEC20L and SEC22B (the assembly has been described as syntaxin 18 complex); links NRZ to SNARE USE1 (PubMed:19369418). Broadly expressed, with highest levels in heart and skeletal muscle, and lowest levels in liver, small intestine and thymus. Well expressed in retinal ganglion cells, epidermal skin cells, and leukocytes. Up-regulated together with N-myc in some neuroblastoma cell lines. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. NBAS mutations have been found in a multisystem disease affecting the liver, eye, immune system, connective tissue, and bone. Clinical manifestations include a progeroid appearance, short stature, slender bones, epiphyseal dysplasia with multiple phalangeal pseudo-epiphyses, cervical instability, myelopathy, elevated transaminases, hypogammaglobulinemia, reduced natural killer cells, Pelger-Huet anomaly of granulocytes, and in some cases retinal dystrophy and optic atrophy. Truncated N-terminus. Extended C-terminus. Truncated N-terminus.