Disease relevance of P56LCK

• One of these 42,000-dalton proteins was shown previously to be phosphorylated on tyrosine in chicken embryo cells transformed with various retroviruses whose transforming proteins possess tyrosine protein kinase activity [1].
• The transforming protein P68gag-ros of avian sarcoma virus UR2 is a transmembrane tyrosine protein kinase molecule with the gag portion protruding extracellularly [2].
• The TPK previously detected in the murine lymphoma (LSTRA) induced by the Moloney murine leukemia virus phosphorylates gastrin, the apparent Km is 65 microM and the maximum rate 1900 pmol/min per mg; the kinase is more efficient with MnCl2 than with MgCl2, is stimulated by NaVO3 and inhibited by ZnCl2 [3].

High impact information on P56LCK

• We demonstrate here that the ATP analogue p-fluorosulphonylbenzoyl 5'-adenosine (FSBA) inactivates the tyrosine protein kinase activity of p60src by reacting with lysine 295 [4].
• In contrast, alterations of tyrosine residues present at positions 511 or 519 in c-src do not induce transformation or in vivo tyrosine protein kinase activity [5].
• The role of tyrosine phosphorylation in the regulation of tyrosine protein kinase activity was investigated using site-directed mutagenesis to alter the structure and environment of the three tyrosine residues present in the C terminus of avian pp60c-src [5].
• Discrete primary locations of a tyrosine-protein kinase and of three proteins that contain phosphotyrosine in virally transformed chick fibroblasts [6].
• In addition, we show that a tyrosine protein kinase activity is associated only with the gp70 protein in microsomes and in immune complexes [7].

Biological context of P56LCK

• Our earlier study predicted that proto-oncogene c-ros codes for a receptor-like tyrosine protein kinase (TPK) [8].
• Nucleotide sequence of the c-ros cDNA predicts that it codes for a transmembrane (TM) TPK molecule of 2311 amino acids (aa) [8].
• The predicted amino acid sequence of the chicken c-ros protein differs by 25% from that of its closest known human counterparts within the tyrosine protein kinase catalytic domain, and by 66% downstream of this domain [9].
• The present study demonstrates that signal transduction through a receptor lacking intrinsic tyrosine protein kinase activity involves a rapid and potent phosphorylation of a non-receptor tyrosine protein kinase in the membranes [10].
• The two classes of c-src mRNA most likely are generated by alternative splicing, and the smaller c-src RNA most likely codes for a product other than tyrosine protein kinase [11].

Anatomical context of P56LCK

• The major species of tyrosine protein kinase of rat liver, has been purified to near homogeneity from liver cytosol [12].
• Previous studies showed that VIP modulates mediators of two signal transduction pathways, namely the adenylate cyclase and the nonreceptor tyrosine protein kinase pp60c-src in cultured chick retinal pigment epithelium (RPE) [13].

Associations of P56LCK with chemical compounds

• Modification of synthetic peptides related to lactate dehydrogenase (231-242) by protein carboxyl methyltransferase and tyrosine protein kinase: effects of introducing an isopeptide bond between aspartic acid-235 and serine-236 [14].

Physical interactions of P56LCK

• Avian CD4 and CD8 interact with a cellular tyrosine protein kinase homologous to mammalian p56lck [15].

Other interactions of P56LCK

• We have tested the possibility that tkl, a partially characterized avian tyrosine protein kinase gene, is the chicken homolog of lck, a lymphocyte-specific mammalian gene [16].
• A discontinuous epitope on p36, the major substrate of src tyrosine-protein-kinase, brings the phosphorylation site into the neighbourhood of a consensus sequence for Ca2+/lipid-binding proteins [17].
• The results presented in this report demonstrate that the avian CD4 and CD8 homologs are physically associated with a cellular tyrosine protein kinase related to mammalian p56lck [15].

References