A SETD2-CDK1-lamin axis maintains nuclear morphology and genome stability.

Histone methyltransferases regulate chromatin organization and are frequently mutated in human diseases, including cancer. One such often mutated methyltransferase, SETD2, associates with transcribing RNA polymerase II and catalyses H3K36me3-a modification that contributes to gene transcription, splicing and DNA repair. Although its catalytic function is well-characterized, its non-catalytic roles remain unclear. Here we reveal a catalysis-independent function of SETD2 in nuclear lamina stability and genome integrity. Through its intrinsically disordered amino terminus, SETD2 associates with lamina-associated proteins, including lamin A/C, lamin B1 and emerin. Loss of SETD2 or its N terminus leads to severe nuclear morphology defects and genome instability, mirroring lamina dysfunction. Mechanistically, the N terminus of SETD2 serves as a scaffold for the mitotic kinase CDK1 and lamins, facilitating lamin phosphorylation and depolymerization during mitosis. Restoration of the N-terminal regions required for interaction with CDK1 and lamins rescues nuclear morphology and suppresses tumorigenic growth in a clear cell renal cell carcinoma model with SETD2 haploinsufficiency. These findings reveal a previously unrecognized role of SETD2 in nuclear lamina organization and genome maintenance that probably extends to its role as a tumour suppressor.