Import of proteins with classical NLS composed of one or two clusters of basic residues is initiated by binding to the importin alpha/beta heterodimer, where importin alpha acts as an adapter subunit to bridge NLS cargos to importin beta, which transports the whole complex through the nuclear envelope (PubMed:12684370). Involved in the nuclear accumulation of the light-dependent developmental regulator veA (PubMed:17163983, PubMed:19318129). Participates at different regulatory stages of asexual and sexual development, being required for the completion of both reproductive cycles with the formation of conidiospores and ascospores, respectively (PubMed:19318129). Mediates secondary metabolite gene expression with positive regulation of penicillin production and negative regulation of mycotoxin biosynthesis (PubMed:19318129). Forms a complex with an importin beta subunit (By similarity). Interacts with hsp70, hsp90, napB, nkuA, nudK, AN1413 and nimE (PubMed:17890114). Leads to lethality (PubMed:19318129). Belongs to the importin alpha family.