TBC1 domain family member 17 (TBC1D17)

Probable GTPase-activating protein for Rab8; its transient association with Rab8 is mediated by OPTN. Inhibits Rab8-mediated endocytic trafficking, such as of transferrin receptor (TfR) and reduces Rab8 recruitnment into tubules emanating from the endocytic recycling compartment (ERC).

Involved in regulation of autophagy. Mediates inhibition of autophagy caused by the OPTN version GLC1E LYS-50; the function requires its catalytic activity, however, the involved Rab isn't known.