Optineurin was identified as an autophagy receptor. Function of optineurin in autophagy depends on its ability to bind directly with LC3 and ubiquitin through well defined binding sites. Involvement of autophagy and proteasome in E50K-induced cell death has been suggested earlier but the mechanisms are not understood. Our results show that mutation of LC3-binding site or UBD by point mutations reduced E50K-induced cell death suggesting that these interactions play an important role in E50Kinduced cell death. The vesicle-like structures formed by E50KOPTN expression were all positive for TFR. Many but not all the vesicles formed were also positive for the autophagosome marker, LC3, suggesting that these structures were formed partly due to inhibition of autophagy. Therefore, it is likely that the E50K foci, which are positive for TFR but not for LC3 are formed due to alternate mechanisms such as inhibition of vesicle trafficking. Although several glaucoma-associated mutants of optineurin have been tested to induce death of retinal cells, only E50K and M98K variants are able to induce more cell death than wild type optineurin. M98K polymorphism is associated with glaucoma in certain ethnic groups. Like E50K mutant, M98K-OPTN induces cell death selectively in retinal cells but not in other cell lines tested. But, unlike E50K-induced cell death, M98K-induced cell death is not inhibited by antioxidants or antiapoptotic protein Bcl2. Expression of M98K induces autophagy leading to transferrin receptor degradation and cell death. TFR degradation is not seen upon E50K expression indicating that the two variants signal to cell death by engaging different effectors. M98K-OPTN-induced cell death involves autophagy which can be prevented by knockdown of Atg5, a protein essential for autophagy, or by inhibition of autophagy by chemical inhibitors. Transferrin receptor degradation by autophagy plays a crucial role in M98K-induced cell death as shown by nearly complete inhibition of M98K-induced cell death upon coexpression of TFR. Thus an appropriate level of autophagy is essential for survival of retinal cells because enhanced autophagy, as seen with M98K-OPTN, or a block in autophagy, as shown by E50K-OPTN, can lead to cell death. Our results suggest that TBC1D17, through its catalytic activity, mediates E50K-dependent inhibition of autophagy that leads to cell death. Previously we have shown that TBC1D17 mediates E50K-dependent inhibition of TFR recycling. Results presented here suggest that impairment of TFR function partly contributes to E50K-induced cell death because coexpression of TFR reduced this cell death. Thus it appears that in E50Kinduced cell death, TBC1D17 performs two different functions, inhibition of autophagy and inhibition of TFR recycling. Inhibition of TFR recycling by TBC1D17 is due to its ability to inhibit Rab8. However, it is not clear as to how TBC1D17 inhibits autophagy.