SLAMF7 and Miyoshi myopathy: Herein, we demonstrate that the CARtein system targeting BCMA, SLAMF7 or both antigens simultaneously, allows Jurkat T cells to elicit a specific activation response against MM cells, which makes the CARtein platform an attractive approach for multiple targeting through modular CAR T-cell therapy, as the junction between modules is mediated by a covalent peptide linkage and the proteins responsible for binding are not present in the final CAR sequence.