The present disclosure provides RNA-guided CRISPR-Cas effector proteins, nucleic acids encoding same, and compositions comprising same. The present disclosure provides ribonucleoprotein complexes comprising: an RNA-guided CRISPR-Cas effector protein of the present disclosure; and a guide RNA. The present disclosure provides methods of modifying a target nucleic acid, using an RNA-guided CRISPR-Cas effector protein of the present disclosure and a guide RNA. The present disclosure provides methods of modulating transcription of a target nucleic acid.