RUN domain found in RUN and FYVE domain-containing proteins, RUFY1, RUFY2, RUFY3 and similar proteins
This family includes RUN and FYVE domain-containing protein RUFY1, RUFY2, and RUFY3. RUFY1, also called FYVE-finger protein EIP1, or La-binding protein 1, or Rab4-interacting protein (Rabip4), or Zinc finger FYVE domain-containing protein 12 (ZFY12), a human homolog of mouse Rabip4, an effector of Rab4 GTPase that regulates recycling of endocytosed cargo. RUFY1 is an endosomal protein that functions as a dual effector of Rab4 and Rab14 and is involved in efficient recycling of transferrin (Tfn). It is a downstream effector of Etk, a downstream tyrosine kinase of PI3-kinase that is involved in regulation of vesicle trafficking. RUFY2, also called Rab4-interacting protein related, is a novel embryonic factor that is present in the nucleus at early stages of embryonic development. It may have both endosomal functions in the cytoplasm and nuclear functions. RUFY3, also called Rap2-interacting protein x (RIPx or RPIPx), or single axon-regulated protein (singar), is an N-terminal RUN domain and a C-terminal FYVE domain containing protein predominantly expressed in the brain. It suppresses formation of surplus axons for neuronal polarity. Unlike other RUFY proteins, RUFY3 can associate with the GTP-bound active form of Rab5. RUFY1, RUFY2, and RUFY3 contain an N-terminal RUN domain and a C-terminal FYVE domain with two coiled-coil domains in-between; this model represents the RUN domain.