InterPro domain: IPR044783

Phytolongin is a longin-related family of proteins specific to plants. Similar to longin, they contain the N-terminal longin domain and the C-terminal transmembrane domain. However, the central SNARE motif is replaced in Phytolongins is replaced by another domain termed the 'Phyl domain'. Phylogenetic analysis revealed that the Phytolongins are derivatives of the plant specific VAMP72 longin sub-family and allows elucidation of Phytolongin evolution. These proteins are involved in membrane-trafficking machinery [ 1 , 2 ].

Four phytolongins in Arabidopsis have been shown to be distributed along the secretory pathway: Phyl2.1 and Phyl2.2 are strictly located at the endoplasmic reticulum network, Phyl1.2 associates with the Golgi bodies, and Phyl1.1 locates mainly at the plasma membrane and partially in the Golgi bodies and post-Golgi compartments [ 3 ].

1. Comparative analysis of plant genomes allows the definition of the "Phytolongins": a novel non-SNARE longin domain protein family. BMC Genomics 10, 510
2. Subcellular localization and trafficking of phytolongins (non-SNARE longins) in the plant secretory pathway. J Exp Bot 67, 2627-2639