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Proximity Proteomics Revealed Dicer1 and Transporters as Client Proteins of Aha1

ABSTRACT: Co-chaperone Aha1 activates HSP90 ATPase to promote the folding of client proteins. However, the client proteins of Aha1 are largely unknown. By employing ascorbate peroxidase (APEX) based proximity labeling, we identified 32 proximity proteins of HSP90 that are modulated by genetic depletion of Aha1. Among them, Dicer1 is one of the top-ranked proteins, which were further confirmed by streptavidin pull-down followed by Western blot analysis, demonstrating the reliability of the approach. Flag pull-down result showed interactions between endogenous HSP90 and Dicer1 and Aha1. The Dicer1 level is regulated synergistically by Aha1 and HSP90. Maturation-dependent interaction results showed a preferential binding of Aha1 and HSP90 to nascently translated Dicer1. Reconstitution of Aha1-depleted cells with WT Aha1 restored Dicer1 level, while the HSP90-binding-defective E67K mutant exhibited partial restoration. Moreover, knockdown of Aha1 and inhibition of HSP90 can diminish the levels of mature miRNA, let-7b and mir-30a. Overall, our study uncovers, for the first time, Dicer1 and transporter proteins as clients of Aha1 and HSP90.

INSTRUMENT(S): Q Exactive Plus

ORGANISM(S): Homo Sapiens (human) Pan Troglodytes (chimpanzee)

TISSUE(S): Permanent Cell Line Cell

SUBMITTER: Yen-Yu Yang

LAB HEAD: Yinsheng Wang

PROVIDER: PXD028980 | Pride | 2022-11-19

REPOSITORIES: Pride

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