Annotations: 8S6Z

CD28 in complex with the antibody Fab fragment AI3

External Resource: Annotation

Domain Annotation: SCOP2 Classification
Domain Annotation: ECOD Classification
SAbDab Antibody Annotation
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
C	SCOP2B Superfamily	Immunoglobulin (Ig) domain-like	8054535	3000071	SCOP2B (2022-06-29)
F	SCOP2B Superfamily	Immunoglobulin (Ig) domain-like	8054535	3000071	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	Rap1-DNA-bind	e8s6zA1	A: alpha arrays	X: HTH	H: HTH	T: Three-helical HTH	F: Rap1-DNA-bind	ECOD (v295)
D	Rap1-DNA-bind	e8s6zD1	A: alpha arrays	X: HTH	H: HTH	T: Three-helical HTH	F: Rap1-DNA-bind	ECOD (v295)
B		e8s6zB01	A: alpha arrays	X: HTH	H: HTH	T: Three-helical HTH	F:	ECOD (v295)
E	Rap1-DNA-bind	e8s6zE1	A: alpha arrays	X: HTH	H: HTH	T: Three-helical HTH	F: Rap1-DNA-bind	ECOD (v295)
C		e8s6zC01	A: alpha arrays	X: HTH	H: HTH	T: Three-helical HTH	F:	ECOD (v295)
F	Rap1-DNA-bind	e8s6zF1	A: alpha arrays	X: HTH	H: HTH	T: Three-helical HTH	F: Rap1-DNA-bind	ECOD (v295)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
A, D	Heavy Chain	IGHV3	-	t-cell-specific surface glycoprotein cd28	SAbDab (2026-08-07)
B, E	Light Chain	IGKV4	Kappa	t-cell-specific surface glycoprotein cd28	SAbDab (2026-08-07)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
C, F	PF15910	ICOS V-set domain (V-set_2)	ICOS V-set domain	This family contains divergent V-set ig domains found in the ICOS protein.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, D	Heavy chain Fab fragment of AI3 antibody	-	-	-
B, E	Light chain of AI3 antibody	-	-	-
C, F	T-cell-specific surface glycoprotein CD28	molecular transducer activity coreceptor activity signaling receptor activity protein binding binding kinase binding enzyme binding protein kinase binding identical protein binding transmembrane signaling receptor activity	cellular response to stimulus immune response-regulating cell surface receptor signaling pathway regulation of cellular process response to stimulus signaling positive regulation of biological process cell communication positive regulation of response to stimulus immune response-activating signaling pathway immune response-regulating signaling pathway positive regulation of immune response regulation of immune system process signal transduction positive regulation of immune system process cellular response to stimulus immune response-regulating cell surface receptor signaling pathway regulation of cellular process response to stimulus signaling positive regulation of biological process cell communication positive regulation of response to stimulus immune response-activating signaling pathway immune response-regulating signaling pathway positive regulation of immune response regulation of immune system process signal transduction positive regulation of immune system process regulation of biological process cell surface receptor signaling pathway immune response-activating cell surface receptor signaling pathway immune response biological regulation T cell receptor signaling pathway regulation of response to stimulus immune system process regulation of immune response cellular process antigen receptor-mediated signaling pathway activation of immune response humoral immune response negative regulation of programmed cell death regulation of apoptotic process negative regulation of biological process regulation of programmed cell death cell death negative regulation of apoptotic process negative regulation of cellular process apoptotic process programmed cell death regulation of biosynthetic process regulation of macromolecule metabolic process gene expression macromolecule biosynthetic process positive regulation of macromolecule biosynthetic process regulation of gene expression positive regulation of metabolic process biosynthetic process positive regulation of gene expression positive regulation of biosynthetic process regulation of macromolecule biosynthetic process metabolic process positive regulation of macromolecule metabolic process macromolecule metabolic process regulation of metabolic process positive regulation of cellular process positive regulation of organelle organization regulation of cellular component organization positive regulation of cellular component organization regulation of mitotic nuclear division positive regulation of mitotic nuclear division mitotic cell cycle cellular component organization regulation of mitotic cell cycle positive regulation of cell cycle process cellular component organization or biogenesis cell cycle regulation of cell cycle cell cycle process mitotic nuclear division regulation of cell cycle process organelle fission positive regulation of nuclear division regulation of organelle organization positive regulation of cell cycle organelle organization nuclear division mitotic cell cycle process regulation of nuclear division developmental process multicellular organismal process cellular developmental process hemopoiesis cell activation cell development mononuclear cell differentiation lymphocyte activation lymphocyte differentiation leukocyte activation T cell activation cell differentiation regulatory T cell differentiation anatomical structure development T cell differentiation leukocyte differentiation positive regulation of cell communication positive regulation of signal transduction positive regulation of T cell receptor signaling pathway regulation of antigen receptor-mediated signaling pathway regulation of signal transduction regulation of signaling regulation of T cell receptor signaling pathway regulation of cell communication positive regulation of antigen receptor-mediated signaling pathway positive regulation of signaling positive regulation of protein metabolic process positive regulation of translation protein biosynthetic process regulation of primary metabolic process post-transcriptional regulation of gene expression protein metabolic process regulation of protein metabolic process primary metabolic process translation regulation of translation positive regulation of viral genome replication positive regulation of viral process viral life cycle regulation of viral life cycle regulation of viral process viral genome replication viral process regulation of viral genome replication regulation of cytokine production cytokine production regulation of multicellular organismal process regulation of interleukin-2 production interleukin-2 production positive regulation of interleukin-2 production positive regulation of multicellular organismal process positive regulation of cytokine production interleukin-10 production regulation of interleukin-10 production positive regulation of interleukin-10 production regulation of leukocyte activation regulation of cell activation positive regulation of leukocyte cell-cell adhesion leukocyte cell-cell adhesion positive regulation of cell-cell adhesion positive regulation of lymphocyte activation positive regulation of cell activation cell adhesion cell-cell adhesion positive regulation of leukocyte activation regulation of cell-cell adhesion positive regulation of T cell activation positive regulation of cell adhesion regulation of cell adhesion regulation of T cell activation lymphocyte costimulation regulation of leukocyte cell-cell adhesion T cell costimulation regulation of lymphocyte activation negative regulation of metabolic process negative regulation of gene expression negative regulation of biosynthetic process negative regulation of macromolecule biosynthetic process negative regulation of macromolecule metabolic process regulation of interleukin-4 production positive regulation of interleukin-4 production interleukin-4 production positive regulation of cell population proliferation lymphocyte proliferation regulation of leukocyte proliferation cell population proliferation positive regulation of lymphocyte proliferation positive regulation of T cell proliferation regulation of cell population proliferation mononuclear cell proliferation positive regulation of leukocyte proliferation leukocyte proliferation positive regulation of mononuclear cell proliferation T cell proliferation regulation of lymphocyte proliferation regulation of T cell proliferation regulation of mononuclear cell proliferation	cell periphery cellular anatomical structure cell surface membrane plasma membrane external side of plasma membrane side of membrane intracellular anatomical structure cytoplasm cytosol immunological synapse protein-containing complex protein complex involved in cell adhesion

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
C, F	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
C, F	IPR013106	Immunoglobulin V-set domain	Domain
C, F	IPR040216	Cytotoxic T-lymphocyte protein 4/CD28	Family
C, F	IPR008093	T cell antigen CD28	Family
C, F	IPR013783	Immunoglobulin-like fold	Homologous Superfamily

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
C, F	: P10747	rheumatoid arthritis autoimmune disease adult T-cell leukemia/lymphoma HIV infectious disease mature T-cell and NK-cell non-Hodgkin lymphoma mycosis fungoides primary cutaneous T-cell non-Hodgkin lymphoma chronic beryllium disease Sezary syndrome Chloracne lymphatic system disease acute T cell leukemia sarcoidosis Sjogren syndrome cancer rheumatoid arthritis autoimmune disease adult T-cell leukemia/lymphoma HIV infectious disease mature T-cell and NK-cell non-Hodgkin lymphoma mycosis fungoides primary cutaneous T-cell non-Hodgkin lymphoma chronic beryllium disease Sezary syndrome Chloracne lymphatic system disease acute T cell leukemia sarcoidosis Sjogren syndrome cancer granulomatous slack skin disease interstitial cystitis osteosarcoma primary biliary cholangitis psoriasis sclerosing cholangitis celiac disease cutaneous lupus erythematosus Hashimoto thyroiditis lung cancer ovarian cancer primary cutaneous T-cell lymphoma arthritic joint disease demyelinating disease hematologic disease inflammatory bowel disease

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RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729. RCSB PDB uses resources of the National Energy Research Scientific Computing Center (NERSC), a Department of Energy User Facility.