BAG family molecular chaperone regulator 3 is a protein that in humans is encoded by the BAG3 gene. BAG3 is involved in chaperone-assisted selective autophagy. [5] [6] [7] [8] [9]
BAG proteins compete with Hip-1 for binding to the Hsc70/Hsp70 ATPase domain and promote substrate release. All the BAG proteins have an approximately 45-amino acid BAG domain near the C terminus but differ markedly in their N-terminal regions. The protein encoded by this gene contains a WW domain in the N-terminal region and a BAG domain in the C-terminal region. The BAG domains of BAG1, BAG2, and BAG3 interact specifically with the Hsc70 ATPase domain in vitro and in mammalian cells. All 3 proteins bind with high affinity to the ATPase domain of Hsc70 and inhibit its chaperone activity in a Hip-repressible manner. [7]
BAG gene has been implicated in age related neurodegenerative diseases such as Alzheimer's. It has been demonstrated that BAG1 and BAG3 regulate the proteasomal and lysosomal protein elimination pathways, respectively. [10] [11] It has also been shown to be a cause of familial dilated cardiomyopathy. [12] That BAG3 mutations are responsible for familial dilated cardiomyopathy is confirmed by another study describing 6 new molecular variants (2 missense and 4 premature Stops ). Moreover, the same publication reported that BAG3 polymorphisms are also associated with sporadic forms of the disease together with HSPB7 locus. [13]
In muscle cells, BAG3 cooperates with the molecular chaperones Hsc70 and HspB8 to induce the degradation of mechanically damaged cytoskeleton components in lysosomes. This process is called chaperone-assisted selective autophagy and is essential for maintaining muscle activity in flies, mice and men. [8]
BAG3 is able to stimulate the expression of cytoskeleton proteins in response to mechanical tension by activating the transcription regulators YAP1 and WWTR1. [9] BAG3 balances protein synthesis and protein degradation under mechanical stress.
PLCG1 has been shown to interact with:
Tropomyosin receptor kinase C (TrkC), also known as NT-3 growth factor receptor, neurotrophic tyrosine kinase receptor type 3, or TrkC tyrosine kinase is a protein that in humans is encoded by the NTRK3 gene.
Tyrosine-protein phosphatase non-receptor type 11 (PTPN11) also known as protein-tyrosine phosphatase 1D (PTP-1D), Src homology region 2 domain-containing phosphatase-2 (SHP-2), or protein-tyrosine phosphatase 2C (PTP-2C) is an enzyme that in humans is encoded by the PTPN11 gene. PTPN11 is a protein tyrosine phosphatase (PTP) Shp2.
Adapter molecule crk also known as proto-oncogene c-Crk is a protein that in humans is encoded by the CRK gene.
Lymphocyte cytosolic protein 2, also known as LCP2 or SLP-76, is a signal-transducing adaptor protein expressed in T cells and myeloid cells and is important in the signaling of T-cell receptors (TCRs). As an adaptor protein, SLP-76 does not have catalytic functions, primarily binding other signaling proteins to form larger signaling complexes. It is a key component of the signaling pathways of receptors with immunoreceptor tyrosine-based activation motifs (ITAMs) such as T-cell receptors, its precursors, and receptors for the Fc regions of certain antibodies. SLP-76 is expressed in T-cells and related lymphocytes like natural killer cells.
Tyrosine-protein kinase ITK/TSK also known as interleukin-2-inducible T-cell kinase or simply ITK, is a protein that in humans is encoded by the ITK gene. ITK is a member of the TEC family of kinases and is highly expressed in T cells.
JAK1 is a human tyrosine kinase protein essential for signaling for certain type I and type II cytokines. It interacts with the common gamma chain (γc) of type I cytokine receptors, to elicit signals from the IL-2 receptor family, the IL-4 receptor family, the gp130 receptor family. It is also important for transducing a signal by type I (IFN-α/β) and type II (IFN-γ) interferons, and members of the IL-10 family via type II cytokine receptors. Jak1 plays a critical role in initiating responses to multiple major cytokine receptor families. Loss of Jak1 is lethal in neonatal mice, possibly due to difficulties suckling. Expression of JAK1 in cancer cells enables individual cells to contract, potentially allowing them to escape their tumor and metastasize to other parts of the body.
Phosphatidylinositol 3-kinase regulatory subunit alpha is an enzyme that in humans is encoded by the PIK3R1 gene.
Tyrosine-protein phosphatase non-receptor type 6, also known as Src homology region 2 domain-containing phosphatase-1 (SHP-1), is an enzyme that in humans is encoded by the PTPN6 gene.
Cbl is a mammalian gene encoding the protein CBL which is an E3 ubiquitin-protein ligase involved in cell signalling and protein ubiquitination. Mutations to this gene have been implicated in a number of human cancers, particularly acute myeloid leukaemia.
Tyrosine-protein kinase HCK is an enzyme that in humans is encoded by the HCK gene.
Phospholipase C, gamma 1, also known as PLCG1 and PLCgamma1, is a protein that in humans involved in cell growth, migration, apoptosis, and proliferation. It is encoded by the PLCG1 gene and is part of the PLC superfamily.
Insulin receptor substrate 2 is a protein that in humans is encoded by the IRS2 gene.
Fibroblast growth factor receptor 4 is a protein that in humans is encoded by the FGFR4 gene. FGFR4 has also been designated as CD334.
BAG family molecular chaperone regulator 1 is a protein that in humans is encoded by the BAG1 gene.
GRB2-associated-binding protein 1 is a protein that in humans is encoded by the GAB1 gene.
Growth arrest – specific 6, also known as GAS6, is a human gene coding for the GAS6 protein. It is similar to the Protein S with the same domain organization and 43% amino acid identity. It was originally found as a gene upregulated by growth arrested fibroblasts.
Cytoplasmic protein NCK1 is a protein that in humans is encoded by the NCK1 gene.
1-Phosphatidylinositol-4,5-bisphosphate phosphodiesterase gamma-2 is an enzyme that in humans is encoded by the PLCG2 gene.
Tyrosine-protein kinase BLK, also known as B lymphocyte kinase, is a non-receptor tyrosine kinase that in humans is encoded by the BLK gene. It is of the Src family of tyrosine kinases.
BAG family molecular chaperone regulator 4 is a protein that in humans is encoded by the BAG4 gene.