Dynamin-like GTPase that mediates homotypic ER fusion%3B has a role in ER morphology%3B interacts physically and genetically with Yop1p and Rtn1p%3B functional ortholog of the human atlastin ATL1%2C defects in which cause a form of the human disease hereditary spastic paraplegia%3B homolog of Arabidopsis RHD3