PubMed:8384581 JSONTXT

{"project":"AIMed","denotations":[{"id":"T1","span":{"begin":4,"end":26},"obj":"protein"},{"id":"T2","span":{"begin":47,"end":73},"obj":"protein"},{"id":"T3","span":{"begin":97,"end":119},"obj":"protein"},{"id":"T4","span":{"begin":121,"end":127},"obj":"protein"},{"id":"T5","span":{"begin":371,"end":377},"obj":"protein"},{"id":"T6","span":{"begin":405,"end":431},"obj":"protein"},{"id":"T7","span":{"begin":451,"end":463},"obj":"protein"},{"id":"T8","span":{"begin":508,"end":518},"obj":"protein"},{"id":"T9","span":{"begin":604,"end":614},"obj":"protein"},{"id":"T10","span":{"begin":675,"end":681},"obj":"protein"},{"id":"T11","span":{"begin":701,"end":707},"obj":"protein"},{"id":"T12","span":{"begin":743,"end":755},"obj":"protein"},{"id":"T13","span":{"begin":760,"end":780},"obj":"protein"}],"text":"The retinoblastoma protein associates with the protein phosphatase type 1 catalytic subunit.\nThe retinoblastoma protein (p110RB) interacts with many cellular proteins in complexes potentially important for its growth-suppressing function. We have developed and used an improved version of the yeast two-hybrid system to isolate human cDNAs encoding proteins able to bind p110RB. One clone encodes a novel type 1 protein phosphatase catalytic subunit (PP-1 alpha 2), which differs from the originally defined PP-1 alpha by an amino-terminal 11-amino-acid insert. In vitro-binding assays demonstrated that PP-1 alpha isoforms preferentially bind the hypophosphorylated form of p110RB. Moreover, similar p110RB sequences are required for binding PP-1 alpha 2 and SV40 large T antigen. Cell cycle synchrony experiments revealed that this association occurs from mitosis to early G1. The implications of these findings on the regulation of both proteins are discussed."}