The function of CALR3 (calreticulin 3, Ensembl gene identifier ENSG00000269058) is as follows. During spermatogenesis, may act as a lectin-independent chaperone for specific client proteins such as ADAM3. Required for sperm fertility (By similarity). CALR3 capacity for calcium-binding may be absent or much lower than that of CALR. {ECO:0000250, ECO:0000269|PubMed:21590275}.