Addition of soluble TGF-β1 alters the levels of cyclin D2, not cyclin D3, cdk2, cdk4, or cdk6.

After incubating with and without soluble TGF-β1 for 18 hours, CD34⁺ progenitors were lysed in 1% NP-40, loaded onto a 10% or 15% SDS-PAGE gel, and transferred to Immunobilon PSQ membrane. Immunoblotting with antibodies to cdk4 (SC-749), cdk6 (SC-7961), cyclin D2 (SC-754), cyclin D3 (D-7), and p15 (SC-613) was then performed.