Drosophila nephrocytes are functionally homologous to vertebrate kidney podocytes; in both, slit diaphragms function as molecular filters during the process of blood and haemolymph filtration. In Drosophila larval nephrocytes, it has been shown that that diaphragm stability and the balance between slit diaphragm damage and repair are controlled by SRC-dependent phosphorylation of diaphragm components (FBrf0223688). This work was done using the fly Src family kinase, Src64B. Loss-of-function alleles, RNAi-targeting constructs, and alleles caused by insertional mutagenesis have been generated for Src64B.
There are multiple members of the Src family of protein tyrosine kinases in both human and Drosophila: 9 human genes and 3 fly genes.
Animals homozygous for an amorphic mutation of Src64B survive to adult stage, but females are semi-sterile. In third-instar larvae, nephrocytes exhibit morphological changes. In a chemically-induced model of kidney disease using fly larvae (FBhh0000545), hyperactivation of Src64B is observed. Many genetic and physical interactions have been described for Dmel\Src64B; see below and in the Src64B gene report.
[updated Jun. 2017 by FlyBase; FBrf0222196]
Loss of Src64B activity leads to a reduction in the number of filtration diaphragms in larval nephrocytes. Diaphragm injury caused by either attenuation or hyperactivation of Src64B can be repaired upon return to physiological levels of Src64B activity. When diaphragm damage is induced by administration of the drug puromycin aminonucleoside, hyperactivation of Src64B is observed.
Src family kinase is a family of non-receptor tyrosine kinases that includes nine members in humans. Src family kinases contain six conserved domains: an N-terminal myristoylated segment, a SH2 domain, a SH3 domain, a linker region, a tyrosine kinase domain, and C-terminal tail. Src family kinases interact with many cellular cytosolic, nuclear and membrane proteins, modifying these proteins by phosphorylation of tyrosine residues. [from HGNC, Gene Family: Src family tyrosine kinases; http://www.genenames.org/cgi-bin/genefamilies/set/1388]
Many to many: Dmel\Src64B is a member of the Src family of protein tyrosine kinases; there are 3 fly genes and 9 human genes in this family. Src64B is most closely related to human SRC and FYN, with which it shares 49-50% identity and 67% similarity. The other fly genes in this family are Src42A and Btk29A.