Immunoglobulin J chain; Serves to link two monomer units of either IgM or IgA. In the case of IgM, the J chain-joined dimer is a nucleating unit for the IgM pentamer, and in the case of IgA it induces larger polymers. It also help to bind these immunoglobulins to secretory component.

POU domain class 2-associating factor 1; Transcriptional coactivator that specifically associates with either OCT1 or OCT2. It boosts the OCT1 mediated promoter activity and to a lesser extent, that of OCT2. It has no intrinsic DNA-binding activity. It recognizes the POU domains of OCT1 and OCT2. It is essential for the response of B-cells to antigens and required for the formation of germinal centers.

Protein disulfide-isomerase A6; May function as a chaperone that inhibits aggregation of misfolded proteins. Negatively regulates the unfolded protein response (UPR) through binding to UPR sensors such as ERN1, which in turn inactivates ERN1 signaling (By similarity). May also regulate the UPR via the EIF2AK3 UPR sensor (By similarity). Plays a role in platelet aggregation and activation by agonists such as convulxin, collagen and thrombin (By similarity). Belongs to the protein disulfide isomerase family.

Endoplasmin; Molecular chaperone that functions in the processing and transport of secreted proteins. When associated with CNPY3, required for proper folding of Toll-like receptors. Functions in endoplasmic reticulum associated degradation (ERAD) (By similarity). Has ATPase activity ; Belongs to the heat shock protein 90 family.

B-cell antigen receptor complex-associated protein alpha chain; Required in cooperation with CD79B for initiation of the signal transduction cascade activated by binding of antigen to the B- cell antigen receptor complex (BCR) which leads to internalization of the complex, trafficking to late endosomes and antigen presentation. Also required for BCR surface expression and for efficient differentiation of pro- and pre-B-cells. Stimulates SYK autophosphorylation and activation. Binds to BLNK, bringing BLNK into proximity with SYK and allowing SYK to phosphorylate BLNK. Also interacts wit [...]

B-lymphocyte antigen CD20; B-lymphocyte-specific membrane protein that plays a role in the regulation of cellular calcium influx necessary for the development, differentiation, and activation of B-lymphocytes. Functions as a store-operated calcium (SOC) channel component promoting calcium influx after activation by the B-cell receptor/BCR. Belongs to the MS4A family.

Endoplasmic reticulum chaperone BiP; Endoplasmic reticulum chaperone that plays a key role in protein folding and quality control in the endoplasmic reticulum lumen. Involved in the correct folding of proteins and degradation of misfolded proteins via its interaction with DNAJC10/ERdj5, probably to facilitate the release of DNAJC10/ERdj5 from its substrate. Acts as a key repressor of the ERN1/IRE1-mediated unfolded protein response (UPR) (By similarity). In the unstressed endoplasmic reticulum, recruited by DNAJB9/ERdj4 to the luminal region of ERN1/IRE1, leading to disrupt the dimeriz [...]

B-cell antigen receptor complex-associated protein beta chain; Required in cooperation with CD79A for initiation of the signal transduction cascade activated by the B-cell antigen receptor complex (BCR) which leads to internalization of the complex, trafficking to late endosomes and antigen presentation. Enhances phosphorylation of CD79A, possibly by recruiting kinases which phosphorylate CD79A or by recruiting proteins which bind to CD79A and protect it from dephosphorylation.

Immunoglobulin lambda-like polypeptide 1; Critical for B-cell development.