Figure 10. Working model: BIPASS: BAG-instructed proteasomal to autophagosomal switch and sorting. When BAG1:BAG3 protein ratio is in favor of BAG1 (1), HSPA1A-bound clients (70) are targeted by BAG1 to the proteasome for degradation (2). Under conditions of proteasomal overload, BAG3 expression is upregulated (3), thus changing the ratio in favor of BAG3. HSPA1A-bound clients are now mainly taken care by BAG3 (4). BAG3 promotes the sequestration of these clients into cytoplasmic puncta that are colabeled with the autophagy adaptor SQSTM1 (p62) and the autophagy marker MAP1LC3B (LC3) (5), to be next rerouted to autophagosomes for degradation (6).