Abstract Loss of expression of VIPAS39/VPS16B or the Sec1/Munc18 (SM) family protein VPS33B causes early lethal ARC syndrome in humans. These proteins have been shown to form a complex containing 2 opposed VPS33B molecules known as VPS33B-VPS16B. ARC patient-derived fibroblasts have dispersed Golgi elements and absence of ribbons, an abnormality also observed in VPS16B-knockout HEK293 cells. These observations indicate that VPS33B-VPS16B is involved in Golgi formation/stability.
