( ( Cyclin A2 ) ( ( belongs ( to ( ( ( the ( cyclin family ) ) , ) ( ( whose members ) ( ( regulate ( cell ( cycle progression ) ) ) ( by ( interacting ( with ( CDK kinases ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Cyclin) (NNP A2)) (VP (VBZ belongs) (PP (TO to) (NP (NP (DT the) (NN cyclin) (NN family)) (, ,) (SBAR (WHNP (WP$ whose) (NNS members)) (S (VP (VB regulate) (NP (NN cell) (NN cycle) (NN progression)) (PP (IN by) (S (VP (VBG interacting) (PP (IN with) (NP (NNP CDK) (NNS kinases)))))))))))) (. .)))
Cyclin A2 belongs to the cyclin family, whose members regulate cell cycle progression by interacting with CDK kinases.
(ROOT (S (NP (NNS Cyclins)) (VP (VB regulate) (NP (DT the) (NN cell) (NN cycle)) (ADVP (RB only)) (SBAR (WHADVP (WRB when)) (S (NP (PRP they)) (VP (VBP are) (ADJP (RB tightly) (VBN bound) (PP (TO to) (NP (NNS cdks)))))))) (. .)))