Probably involved in the organization of the actin cytoskeleton by acting downstream of CDC42, inducing actin filament assembly. Alters CDC42-induced cell shape changes. In activated T-cells, may play a role in CDC42-mediated F-actin accumulation at the immunological synapse. May play a role in early contractile events in phagocytosis in macrophages. Interacts with CDC42 (in GTP-bound form). Interacts weakly with RAC1 and not at all with RHOA. Recruited to the activated TCR prior actin polymerization. Localizes at the phagocytic cup of macrophages. Widely expressed. Expressed at higher level in T-lymphocytes. Highly expressed in CCRF-CEM T-lymphocytes, Jurkat T-lymphocytes, and Raji B-lymphocytes compared (at protein level). The CRIB domain mediates interaction with CDC42. CDC42SE2 is mapped in the genomic region associated with schizophrenia. Belongs to the CDC42SE/SPEC family.