SKIN ABNORMALITY IN AGED FYN(- -) FAK(+/-) MICE/

Focal adhesion kinase (FAK) is a novel non-receptor protein tyrosine k inase implicated in transducing signals from cell surface receptors, I ts association with Fyn, a member of the Src family of tyrosine kinase s, has been observed in cell lines, To examine in vivo the interaction between these two proteins, Fyn-deficient mice were bred with fak het erozygous mutants (Fak deficiency is embryonic lethal), A majority of animals with the double mutation (fyn(-/-) fak(+/-)) displayed a trans ient impairment in thymocyte development at four weeks of age, However , all of them developed skin abnormalities at the age of 8-12 months, The most prominent among abnormalities was a greatly increased number and size of sebaceous glands, Also, the epidermis was thickened and hy perkeratotic, These observations would suggest involvement of Fyn and FAK in keratinocyte differentiation.