Trans-Golgi network vesicle protein 23 A (TVP23A) is a protein coded for the TVP23A gene, formerly known as FAM18A. TVP23A is located on chromosome 16. It is known to have human paralogs, TVP23B and TVP23C, as well as orthologs in many different species, notably yeast, mice, and chickens. The general consensus on the TVP23A protein indicate that it has some function in the late Golgi apparatus and is involved in retrograde transport from endosomes back into the Golgi apparatus. The nature of this transport is still unknown.