Intracellular protein transport is mediated by budding and fusion of transport vesicles on intracellular membrane organelles and often linked to photoreceptor degenerations in human. However, it is unclarified how protein transport defects cause photoreceptor degenerations. We previously reported that mutations of β-SNAP/napbb, a vesicular fusion regulator, cause apoptosis in zebrafish photoreceptors, and found that this apoptosis depends on BNip1. BNip1 is a component of syntaxin18 (stx18) SNARE complex, which regulates retrograde transport from Golgi to ER. BNip1 contains the BH3 domain, which activates the Bax-dependent apoptosis. The absence of β-SNAP compromises the disassembly of stx18 cis-SNARE complex, which is generated by vesicular fusion. Accumulation of stx18 cis-SNARE complex activates Bax-dependent apoptosis through its BH3 domain. Thus, BNip1 induces apoptosis in response to vesicular fusion defects. To understand physiological roles of BNip1 for photoreceptor apoptosis, we examined the relationship between β-SNAP functions and BNip1-mediated apoptosis. In the β-SNAP mutant, photoreceptor degeneration largely occurs at 2-3 dpf in the stage when protein transport is highly activated. We found that over-expression of β-SNAP during 2-5 dpf is enough to suppress photoreceptor apoptosis in the β-SNAP mutant at least by 3 wpf, indicating that BNip1-dependent apoptosis correlates with an excessive activated vesicular transport state, suggesting that BNip1 may be one of safe guard that limits the upper threshold of vesicular transport.