Hck

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Introductions

Tyrosine-protein kinase HCK is an enzyme that in humans is encoded by the HCK gene. The protein encoded by HCK is a protein tyrosine kinase that is expressed primarily in hematopoietic cell types and belongs to the Src family of tyrosine kinases. The encoded protein may help link the Fc receptor to the activation of respiratory bursts. HCK and Src family kinases are also thought to drive the survival of drug-resistant cancer cells. [6] In addition, it may play a role in neutrophil migration and neutrophil degranulation. The alternating use of translation start sites, including a non-AUG (CUG) codon, leads to the generation of two different isoforms that have different subcellular localizations.

Features

• HCK is a subclass of protein kinases.
• HCK is an enzyme that transfers phosphate groups from ATP to tyrosine residues in proteins. Phosphorylation of proteins by kinases is an important mechanism in signal transduction that regulates enzyme activity.
• There are more than 100 three-dimensional structures of HCK in the Protein Data Bank. One example is the crystal structure of PDB 1IRK, the tyrosine kinase structural domain of the human insulin receptor.

Non-receptor type

Represented by the src gene product, in addition to Yes, Fyn, Lck, Fgr, Lyn, Fps/Fes and Ab1. Except for the latter two, the remaining non-receptor type protein tyrosine kinase Src family proteins with molecular weight of about 60 kDa are very similar to each other except for the N-terminal 80 amino acid composition.

Membrane receptor types

Depending on their structures, receptor-type tyrosine kinases can be classified into nine types, of which four types are more common:

• Epidermal growth factor receptor (EGFR) family

Members of the EGFR family include EGF-R (with a molecular weight of 170 kDa and widely expressed in a variety of tissue cells), erbB2/neu and erbB-3 gene expression products. The family members are characterized by two cysteine-rich regions outside the cytosol and a tyrosine kinase activating region in the cytoplasm.

• Insulin receptor family

The family members include insulin receptor (IR), insulin-like growth factor-1 receptor (IGF-1R) and insulin related receptor (IRR). receptor (IRR). Insulin receptor family members are heterotetramers formed by two alpha subunits and two beta subunits through interchain disulfide bonds. The α subunit is the ligand binding site; the intracytoplasmic portion of the β subunit contains the tyrosine kinase active region.

• PDGF/MCSF/SCF receptor family

PDGF/MCSF/SCF receptor family members include platelet-derived growth factor α receptor (PDGF-αR), PDGF-βR, macrophage colony-stimulating factor receptor (M-CSFR) and stem cell growth factor receptor (SCFR). The above members are characterized by the extracellular membrane containing five immunoglobulin-like structural domains and the cytoplasm containing two functional regions of tyrosine kinase in a tandem structure.

• Fibroblast growth factor receptor (FGFR) family

FGFR family members include FGFR1, FGFR2, FGFR3 and FGF4. They are characterized by three immunoglobulin-like structural domains outside the cytosol, including one containing eight consecutive acidic amino acid structures between the first and second structural domains, also known as acid box structural domain. domain); the cytoplasm contains two functional regions of kojic acid kinase in a tandem structure.

Src family

Protein tyrosine kinases belonging to the src family are a group of membrane-bound proteins that include members of p60arc, p56lck, p59fyn, p59yes, (p62ues), p56lyn, p59hck, p55fgr and p55blk. However, because src family PTKs lack extracellular and transmembrane sequences, these src family PTKs function as signal transducers by linking to the intracytoplasmic structural domains of cell membrane surface proteins through their N termini.