May be involved in the control of the cell cycle at the G1/S (start) and G2/M (mitosis) transitions. May primarily function in the control of the germline meiotic cell cycle and additionally in the control of mitotic cell cycle in some somatic cells (By similarity). Interacts with the CDK2 and the CDC2 protein kinases to form a serine/threonine kinase holoenzyme complex. The cyclin subunit imparts substrate specificity to the complex. Does not bind CDK4 and CDK5 (in vitro). The cyclin A1-CDK2 complex interacts with transcription factor E2F-1 and RB proteins. Found in a complex with CDK2, CABLES1 and CCNE1. Interacts with INCA1 and KLHDC9 (By similarity). Polyubiquitinated via 'Lys-11'-linked ubiquitin by the anaphase-promoting complex (APC/C), leading to its degradation by the proteasome. Deubiquitinated and stabilized by USP37 enables entry into S phase (By similarity). Belongs to the cyclin family. Cyclin AB subfamily.