• Official Full Name

    cathepsin B

  • Overview

    Cathepsin B is an enzymatic protein belonging to the peptidase (or protease) families. In humans, it is coded by the CTSB gene. The protein encoded by this gene is a lysosomal cysteine protease composed of a dimer of disulfide-linked heavy and light chains, both produced from a single protein precursor. It is a member of the peptidase C1 family. At least five transcript variants encoding the same protein have been found for this gene.
  • Synonyms

    CTSB; cathepsin B; EC; CPSB; amyloid precursor protein secretase; Cathepsin B1; cysteine protease; APPS; EC 3.4.22; APP secretase; OTTHUMP00000116009; OTTHUMP00000229510; OTTHUMP00000229511; OTTHUMP00000229512; OTTHUMP00000229514; OTTHUMP00000229515; OTTHUMP00000229516;

  • Recombinant Proteins
  • Cell & Tissue Lysates
  • Native Proteins
  • Protein Pre-coupled Magnetic Beads
  • Assay Kits
  • Bovine
  • Branchiostoma belcheri tsingtauense
  • Chicken
  • Cynomolgus Monkey
  • Human
  • Mouse
  • Rat
  • Rhesus Macaque
  • Bovine Tissue
  • E.coli
  • HEK293
  • HEK293T
  • Human Cell
  • Human Liver
  • In Vitro Cell Free System
  • Insect Cell
  • Mammalian Cell
  • Mammalian cells
  • Wheat Germ
  • C
  • His
  • GST
  • His (Fc)
  • Avi
  • Myc
  • DDK
  • Myc|DDK
  • N/A
  • N
Species Cat.# Product name Source (Host) Tag Protein Length Price
Human CTSB-169H Active Recombinant Human CTSB protein, His-tagged HEK293 His Arg18-Ile339
Human CTSB-2099H Recombinant Human CTSB Protein, GST-tagged Wheat Germ GST
Human CTSB-278H Recombinant Human CTSB, His tagged Human Cell His
Human CTSB-26410TH Recombinant Human CTSB, His-tagged E.coli His
Human CTSB-3025HCL Recombinant Human CTSB cell lysate Human Cell N/A
Human CTSB-5328H Native Human Cathepsin B Human Liver N/A
Human CTSB-757H Recombinant Human CTSB Protein, Myc/DDK-tagged, C13 and N15-labeled HEK293T Myc/DDK
Human CTSB-3369H Recombinant Human CTSB Protein, MYC/DDK-tagged HEK293 Myc/DDK
Human CTSB-385H Recombinant Human CTSB protein, His-tagged HEK293 His 322
Human CTSB-5932H Recombinant Human CTSB Protein, Myc/DDK-tagged, C13 and N15-labeled HEK293T Myc/DDK
Human CTSB-3874H Recombinant Human CTSB Protein, Myc/DDK-tagged, C13 and N15-labeled HEK293T Myc/DDK
Human CTSB-2331HF Recombinant Full Length Human CTSB Protein, GST-tagged In Vitro Cell Free System GST 339 amino acids
Human CTSB-279H Recombinant Human CTSB protein, GST-tagged E.coli GST Partial
Human CTSB-2750H-B Recombinant Human CTSB Protein Pre-coupled Magnetic Beads HEK293
Human CTSB-26408TH Native Human CTSB N/A
Human CTSB-785H Recombinant Human CTSB Protein, His-tagged HEK293 His 339
Human CTSB-1882H Recombinant Human CTSB Protein (Leu80-Asp333), N-His tagged E.coli N-His Leu80-Asp333
Human CTSB-5252H Recombinant Human CTSB protein E.coli N/A 82-333aa
Human CTSB-2750H Recombinant Human CTSB Protein, His (Fc)-Avi-tagged HEK293 His (Fc)-Avi
Mouse Ctsb-415M Active Recombinant Mouse Ctsb protein, His-tagged HEK293 His Met 1-Phe 339
Mouse Ctsb-8176M Recombinant Mouse Ctsb protein, His-tagged E.coli His Val129~Asp333 (Accession # P10605)
Mouse Ctsb-28M Recombinant Mouse Ctsb Protein, His-tagged Insect Cell His
Mouse Ctsb-413M Recombinant Mouse Cathepsin B Mammalian cells N/A
Mouse Ctsb-8331M Recombinant Mouse Ctsb Mammalian cells N/A
Mouse CTSB-1885MCL Recombinant Mouse CTSB cell lysate Human Cell N/A
Mouse Ctsb-10530M-B Recombinant Mouse Ctsb Protein Pre-coupled Magnetic Beads HEK293
Mouse Ctsb-10530M Recombinant Mouse Ctsb Protein, His (Fc)-Avi-tagged HEK293 His (Fc)-Avi
Mouse Ctsb-7184M Recombinant Mouse Ctsb Protein, His-tagged His 18-339
Mouse Ctsb-2367M Recombinant Mouse Ctsb Protein, Myc/DDK-tagged HEK293T Myc/DDK
Mouse Ctsb-5635M Recombinant Mouse Ctsb Protein (His18-Phe339), C-His tagged Mammalian cells C-His His18-Phe339
Rat Ctsb-8177R Recombinant Rat Ctsb protein, His-tagged E.coli His Val129~Gln333 (Accession # P00787)
Rat Ctsb-1121R Recombinant Rat Ctsb Protein, His-tagged HEK293 His
Bovine CTSB-188B Active Native Bovine Cathepsin B Bovine Tissue N/A
Branchiostoma belcheri tsingtauense CTSB-1062B Recombinant Branchiostoma belcheri tsingtauense CTSB Protein (Ala15-Asp332), C-His tagged E.coli C-His Ala15-Asp332
Cynomolgus Monkey CTSB-427C Recombinant Cynomolgus CTSB Protein, His-tagged Mammalian Cell His
Cynomolgus Monkey CTSB-175C Recombinant Cynomolgus Monkey CTSB Protein, His (Fc)-Avi-tagged HEK293 His (Fc)-Avi
Cynomolgus Monkey CTSB-175C-B Recombinant Cynomolgus Monkey CTSB Protein Pre-coupled Magnetic Beads HEK293
Rhesus Macaque CTSB-416R Recombinant Rhesus CTSB protein, His-tagged HEK293 His Met1-Phe339
Rhesus Macaque CTSB-1086R Recombinant Rhesus monkey CTSB Protein, His-tagged Mammalian Cell His
Rhesus Macaque CTSB-911R Recombinant Rhesus Macaque CTSB Protein, His (Fc)-Avi-tagged HEK293 His (Fc)-Avi
Rhesus Macaque CTSB-911R-B Recombinant Rhesus Macaque CTSB Protein Pre-coupled Magnetic Beads HEK293
Chicken CTSB-6923C Recombinant Chicken CTSB Mammalian Cell His
Kit-2366 Cathepsin B (CTSB) Inhibitor Screening Kit (Fluorometric) N/A
  • Background
  • Quality Guarantee
  • Case Study
  • Involved Pathway
  • Protein Function
  • Interacting Protein
  • Other Resource
Schematic depiction of the role of CTSB in ferroptosis by activating STING1-dependent autophagy.jpg

Fig1. Schematic depiction of the role of CTSB in ferroptosis by activating STING1-dependent autophagy. (Feimei Kuang, 2020)

What is CTSB protein?

CTSB (cathepsin B) gene is a protein coding gene which situated on the short arm of chromosome 8 at locus 8p23. This gene encodes a member of the C1 family of peptidases. Alternative splicing of this gene results in multiple transcript variants. At least one of these variants encodes a preproprotein that is proteolytically processed to generate multiple protein products. These products include the cathepsin B light and heavy chains, which can dimerize to form the double chain form of the enzyme. This enzyme is a lysosomal cysteine protease with both endopeptidase and exopeptidase activity that may play a role in protein turnover. It is also known as amyloid precursor protein secretase and is involved in the proteolytic processing of amyloid precursor protein (APP). The CTSB protein is consisted of 339 amino acids and its molecular mass is approximately 37.8 kDa.

What is the function of CTSB protein?

CTSB mainly plays a role in the lysosome, which is responsible for the degradation of proteins and other biological macromolecules ingested within the cell, and participates in the protein turnover and energy metabolism of the cell. CTSB is involved in the degradation of proteins and organelles in autophagy, which is crucial for maintaining the stability of the intracellular environment and cell energy balance. CTSBS are capable of cutting extracellular matrix (ECM) components such as collagen and elastin, thus participating in cell migration and tumor cell invasion and metastasis. CTSB plays a role in antigen processing, helping to cut protein substrates into smaller fragments for presentation to the immune system by the Major histocompatibility Complex (MHC).

CTSB Related Signaling Pathway

CTSB is involved in protein degradation during autophagy and interacts with autophagy related proteins such as LC3 to regulate the smooth progress of autophagy flow. CTSB can affect apoptosis through mitochondrial pathway or death receptor pathway, and also participate in the regulation of anti-apoptotic signaling pathways, such as PI3K/Akt and MAPK pathways. CTSB plays a role in tumor invasion, metastasis and angiogenesis, and interacts with molecules such as MMPs (matrix metalloproteinases) and VEGF (vascular endothelial growth factor) to affect tumor progression. CTSB is also involved in other signaling pathways, such as Wnt/β-catenin, Notch, and Hedgehog, which regulate cell proliferation, differentiation, and fate determination.

CTSB Related Diseases

CTSB proteins have been implicated in the occurrence and development of a variety of diseases, especially in metabolic diseases, cardiovascular diseases, cancers, and neurodegenerative diseases. In diabetes, CTSB is associated with the exacerbation of diabetic cardiomyopathy (DCM), affecting cardiac function and structure by promoting NLRP3-mediated pyroptosis. In the field of cancer, CTSB is involved in tumor growth, migration, invasion, and metastasis, and its overexpression is associated with poor prognosis in diseases such as breast cancer. In addition, the up-regulation of CTSB expression is related to tumor progression, and its knockdown can inhibit tumor cell proliferation and tumor formation. In neurodegenerative diseases such as Parkinson's disease, variations in the CTSB gene are associated with increased disease risk and may be involved in the disease process by affecting autophagy and apoptosis pathways.

Bioapplications of CTSB

As a key protease in lysosomes, CTSB is particularly important in tumor therapy, especially in the development of antibody drug conjugators (ADCs). ADCs is a novel drug that combines the targeting of antibodies with cytotoxic drug destruction, among which CTSB is one of the commonly used targets of enzyme lytic Linker. These linkers are designed to be specifically cut by CTSB in the tumor microenvironment, thereby releasing cytotoxic drugs that precisely kill tumor cells.

High Purity

SDS-PAGE (CTSB-2099H).jpg

Fig1. SDS-PAGE (CTSB-2099H)


SDS-PAGE (CTSB-757H).jpg

Fig2. SDS-PAGE (CTSB-757H)

Case Study 1: Eun-Kyung Kim, 2020

Thyroid cancer incidence has increased worldwide; however, investigations of thyroid cancer-related factors as potential prognosis markers remain insufficient. Secreted proteins from the cancer secretome are regulators of several molecular mechanisms and are, thereby, ideal candidates for potential markers. This study aimed to identify a specific factor for thyroid cancer by analyzing the secretome from normal thyroid cells, papillary thyroid cancer (PTC) cells, and anaplastic thyroid cancer cells using mass spectrometry (MS). Cathepsin B (CTSB) showed highest expression in PTC cells compared to other cell lines, and CTSB levels in tumor samples were higher than that seen in normal tissue. Further, among thyroid cancer patients, increased CTSB expression was related to higher risk of lymph node metastasis (LNM) and advanced N stage. Overexpression of CTSB in thyroid cancer cell lines activated cell migration by increasing the expression of vimentin and Snail, while its siRNA-mediated silencing inhibited cell migration by decreasing vimentin and Snail expression. Mechanistically, CTSB-associated enhanced cell migration and upregulation of vimentin and Snail occurred via increased phosphorylation of p38.

Western blot of secreted CTSB levels in conditioned media of cultured thyroid cancer cell lines (top).jpg

Fig1. Western blot of secreted CTSB levels in conditioned media of cultured thyroid cancer cell lines (top).

Western blotting for Snail and vimentin in Nthy-ori-3-1 and 8505C cells after treatment with recombinant CTSB.jpg

Fig2. Western blotting for Snail and vimentin in Nthy-ori-3-1 and 8505C cells after treatment with recombinant CTSB.

Case Study 2: Feimei Kuang, 2020

Ferroptosis is a type of non-apoptotic regulated cell death that involves excessive iron accumulation and subsequent lipid peroxidation. Although the antioxidant mechanisms of ferroptosis have been extensively studied recently, little is known about the interactions between the different organelles that control ferroptosis. This study shows that the translocation of lysosomal cysteine protease cathepsin B (CTSB) into the nucleus is an important molecular event that mediates organelle-specific initiation of ferroptosis in human pancreatic cancer cells. Iron-dependent lysosomal membrane permeability triggers the release of CTSB from the lysosome to nucleus during ferroptosis. Mechanistically, nuclear CTSB accumulation causes DNA damage and subsequent activation of the stimulator of interferon response CGAMP interactor 1 (STING1/STING)-dependent DNA sensor pathway, which ultimately leads to autophagy-dependent ferroptosis.

Intracellular CTSB activity.jpg

Fig3. Intracellular CTSB activity.

Western blot analysis of protein expression in indicated gene knockdown PANC1 cells.jpg

Fig4. Western blot analysis of protein expression in indicated gene knockdown PANC1 cells.

Ctsb involved in several pathways and played different roles in them. We selected most pathways Ctsb participated on our site, such as Adaptive Immune System, Antigen processing and presentation, Assembly of collagen fibrils and other multimeric structures, which may be useful for your reference. Also, other proteins which involved in the same pathway with Ctsb were listed below. Creative BioMart supplied nearly all the proteins listed, you can search them on our site.

Pathway Name Pathway Related Protein
Adaptive Immune SystemACTR1A;MGC174857;CYBB;SPSB2;GRAP2B;KIF20A;PDPK1A;CD300LD;CTSH
Antigen processing and presentationPSME1;KIR2DL4;PSME2;TAP1;HSPA6;HLA-DQA1;HLA-F;HLA-C;CD8A
Assembly of collagen fibrils and other multimeric structuresBMP1A;COL4A3;COL6A1;CTSB;COL4A5;COL5A2;DST;LOX;MMP20
Collagen degradationCOL19A1;ADAM9;ADAM10;MMP12;MMP11;COL9A3;LOC100686744;MGC174152;TLDC2
Degradation of the extracellular matrixMMP15;CTSL1;CTSD;CTSB;MMP20;BSG;COL23A1;TIMP2A;TLL1
Extracellular matrix organizationCOL15A1B;COL16A1;CEACAM8;COL17A1A;ADAMTS18;COL25A1;COL3A1;SERPINH1B;PCOLCEB

Ctsb has several biochemical functions, for example, collagen binding, cysteine-type endopeptidase activity, cysteine-type peptidase activity. Some of the functions are cooperated with other proteins, some of the functions could acted by Ctsb itself. We selected most functions Ctsb had, and list some proteins which have the same functions with Ctsb. You can find most of the proteins on our site.

Function Related Protein
cysteine-type endopeptidase activityCASP10;LGMN;USP34;USP10;USP42;CTSW;CTSL2;CASP6L2;USP45
cysteine-type peptidase activityCAPN12;SOLH;Ctsl;CTSB;CASP3B;CASPBL;USP9;USP17L1P;CASPB
kininogen bindingCTSB;Ctsl;CTSL2;C1QBP
protein self-associationSLC2A1;ABCD3;CBR2;TRP53;AGA;CCDC88C;RYR2;ZSWIM2;AXIN1

Ctsb has direct interactions with proteins and molecules. Those interactions were detected by several methods such as yeast two hybrid, co-IP, pull-down and so on. We selected proteins and molecules interacted with Ctsb here. Most of them are supplied by our site. Hope this information will be useful for your research of Ctsb.


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        Q&As (7)

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        How does CTSB affect extracellular matrix remodeling in conditions like osteoarthritis? 01/28/2022

        CTSB affects extracellular matrix remodeling, relevant in joint diseases like osteoarthritis.

        What role does CTSB play in the pathology of neurodegenerative diseases, such as Alzheimer's? 03/29/2020

        CTSB is implicated in neurodegenerative diseases, potentially contributing to protein aggregation and neuronal damage.

        How do alterations in CTSB expression or activity affect tissue repair and fibrosis? 04/26/2019

        Variations in CTSB expression impact tissue repair processes and the development of fibrosis in various organs.

        What are the mechanisms by which CTSB modulates apoptosis and cell survival? 09/26/2018

        CTSB regulates apoptosis and cell survival, influencing cell fate decisions under stress or damage.

        How does CTSB influence the tumor microenvironment and cancer progression? 08/16/2018

        CTSB can influence cancer progression by modulating the tumor microenvironment and facilitating tumor cell invasion.

        How does CTSB (Cathepsin B) contribute to protein degradation and lysosomal function? 04/01/2018

        CTSB is involved in lysosomal protein degradation, essential for cellular waste disposal and recycling.

        What is the impact of CTSB in inflammatory responses and immune cell activation? 01/04/2018

        CTSB plays a role in inflammation, impacting immune cell function and inflammatory responses.

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