May play a role in CNS development by interacting with growth factors implicated in motor neuron differentiation and survival. May play a role in capillary formation and maintenance during angiogenesis. Modulates BMP activity by affecting its processing and delivery to the cell surface. {ECO:0000269|PubMed:12464430, ECO:0000269|PubMed:12805376}. This is the function of ENSG00000150938 (CRIM1, cysteine rich transmembrane BMP regulator 1).