passages.id: split_6_test_762_passage
passages.type: progene_text
passages.text: These results suggest that assembly or stabilization of D - type cyclin holoenzyme complexes 1 ) is an important step in the activation of Cdk4 / 6 by BCR signals , and 2 ) suffice in providing a mechanism to account for inhibition of BCR - stimulated Rb protein phosphorylation by Fc gamma R .