Igbp1b, also known as alpha4-b, is a gene encoding a protein that binds to the protein phosphatase 2A (PP2A). It plays a role in regulating phosphatase activity, likely within relevant cellular signal transduction pathways. The protein's function is crucial for normal physiological processes in specific tissues [1].

The alpha4-b (Igbp1b) transcript is selectively expressed in the brain and testis, not detected in the spleen, thymus, bone marrow, liver, kidney, lung, heart or muscle. In-situ RNA hybridization shows it is expressed in most neuronal cells in the brain but not in glial cells. The encoded protein is highly homologous (66% identity in amino-acid sequence) to the alpha4 molecule and associates with the catalytic subunit of PP2A (PP2Ac), suggesting its role in regulating phosphatase activity in neuronal cells [1].

In conclusion, Igbp1b is selectively expressed in the brain and testis and plays a role in regulating phosphatase activity in neuronal cells through its association with PP2Ac. Although no KO/CKO mouse model findings were presented, understanding its expression pattern and protein-protein interactions is fundamental for uncovering its role in normal brain and testicular function and potentially related diseases.

References:

1. Maeda, K, Inui, S, Tanaka, H, Sakaguchi, N. . A new member of the alpha4-related molecule (alpha4-b) that binds to the protein phosphatase 2A is expressed selectively in the brain and testis. In European journal of biochemistry, 264, 702-6. doi:. https://pubmed.ncbi.nlm.nih.gov/10491115/