Zinc Finger, FYVE Domain Containing Protein 16 (ZFYVE16)

Endofin is expressed in early endosomes, similar to EEA1. Expression constructs of truncated endofin showed that the FYVE domain is required for endosomal expression, and treatment with the PI3-kinase inhibitor wortmannin showed that endosomal localization of endofin is dependent on PI3-kinase activity. While indirect immunofluorescence showed colocalization of endofin and SARA, coimmunoprecipitation experiments demonstrated that the 2 proteins do not associate with each other.

Unlike SARA, endofin does not affect TGF-beta-induced transcriptional activity. Overexpression of endofin caused endosomal aggregate formation, and these aggregates accumulated EGF and prevented its degradation.