True about the nature of LATS is:

LATS is long acting thyroid stimulating antibody. This is a IgG antibody which binds to TSH receptor and mimics the action of TSH, stimulating adenyl cyclase and increasing the release of thyroid hormones. Almost all individuals with Graves disease have noticeable levels of this antibody. Thyroid stimulating antibody is relatively specific for Graves disease, in contrast to thyroglobulin and thyroid peroxidase antibodies. Ref: Robbin's 8/e, Chapter 24