
<ArticleTitle><prot>HACS1</prot> encodes a novel SH3-SAM adaptor protein differentially expressed in normal and malignant hematopoietic cells.</ArticleTitle>
<AbstractText>SH3 and SAM domains are protein interaction motifs that are predominantly seen in signaling molecules, adaptors, and scaffold proteins. We have identified a novel family of putative adaptor genes that includes <prot>HACS1</prot>. <prot>HACS1</prot> encodes a 441 amino acid protein that is differentially expressed in hematopoietic cells and has restricted expression in human tissues. Its SH3 domain is most similar to the same motif in <prot>Crk</prot> and its SAM domain shares homology with a family of uncharacterized putative scaffold and adaptor proteins. <prot>HACS1</prot> maps to human chromosome 21q11.2 in a region that is frequently disrupted by translocation events in hematopoietic malignancies. Polyclonal antibodies against <prot>HACS1</prot> recognized a 49.5 kDa protein whose mRNA is expressed in human immune tissues, bone marrow, heart, lung, placenta and brain. Cell lines and primary cells from acute myeloid leukemias and multiple myeloma patients express <prot>HACS1</prot>. Immunostaining and cellular fractionation studies localized the <prot>HACS1</prot> protein predominantly to the cytoplasm.</AbstractText>
