MmuEX0024624 @ mm9

Two-yeast hybrid assay was used to examine interaction between various alpha integrins (including splice isoforms of integrin alpha 3 (alpha3A and alpha3B (these differ in presence of penultimae exon HsaEX0032352 (present in A, absent in B)), splice isoforms of integrin alpha 6 (alpha6A and alpha6B) (these differ in the presence of penultimate exon HsaEX0032370 (present in A, absent in B), and splice isoforms of integrin alpha 7 (alpha7A and alpha7B (these differ in presence of penultimate exon HsaEX0032377 (present in A, absent in B)) and four proteins, two of which are described as clones as they were identified in a cDNA screen (Mss4, BIN1, clone 63, and clone 80).

HEK293 overexpressing integrin alpha 7 isoforms alpha7A (contains penultimate exon (HsaEX0032377)) or alpha7B (lacks penultimate exon) are shown to adhere to similar extends to laminin-1, a fragment of laminin-1, and laminin-2. Migration across surfaces with above mentioned laminins is also similar. Overexpression of either integrin alpha 7 isoform negatively affects surface expression other beta1-integrin associated alpha integrin chains (alpha1, alpha3, alpha5, and alpha6). Overexpression also lead to reduced adhesiveness for both isoforms. Note, while they state that the isoforms behave similarly, I do think that their data points toward differences.