Cyclin D1 is enriched in EVs during N2A neurogenesis. (A) Immunoblots of cyclin D, CDK4, Hsc70, Tsg101, and actin of EVs from RA-induced N2A cells for 2, 4, 6, and 8 d (D2, D4, D6, and D8). (B) Immunoblots of pRB, p57, p27, p21, pErk, and actin in differentiated PC12 cells and EVs. (C) Immunoblots of cyclin D1, CDK4, and multiple EV markers from the N6-EVs treated with different concentrations of proteinase K (PK), with or without 1% Triton X-100.