FYVE-related domain found in protrudin and similar proteins
Protrudin, also termed zinc finger FYVE domain-containing protein 27 (ZFY27 or ZFYVE27), is a FYVE domain-containing protein involved in transport of neuronal cargoes and implicated in the onset of hereditary spastic paraplegia (HSP). It is involved in neurite outgrowth through binding to spastin. Moreover, it functions as a key regulator of the Rab11-dependent membrane trafficking during neurite extension. It serves as an adaptor molecule that links its associated proteins, such as Rab11-GDP, VAP-A and -B, Surf4, and RTN3, to KIF5, a motor protein that mediates anterograde vesicular transport in neurons, and thus plays a key role in the maintenance of neuronal function. The FYVE domain of protrudin resembles a FYVE-related domain that is structurally similar to the canonical FYVE domains but lacks the three signature sequences: an N-terminal WxxD motif (x for any residue), the central basic R(R/K)HHCRxCG patch, and a C-terminal RVC motif. In addition, unlike canonical FYVE domains that is located to early endosomes and specifically binds to phosphatidylinositol 3-phosphate (PtdIns3P or PI3P), the FYVE domain of protrudin is located to plasma membrane and preferentially binds phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4)P2), and phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3). In addition to FYVE-related domain, protrudin also contains a Rab11-binding domain (RBD11), two hydrophobic domains, HP-1 and HP-2, an FFAT motif, and a coiled-coil domain.